You popped the question…now what?

Marriage proposal
Jennifer Photography Imaging | Getty Images

The holiday seasonand December, in particularis the most popular time of year to get engaged. About 16 percent of couples get engaged in December alone, according to TheKnot.com's statistics.

But once the euphoria of the engagement wears off, there's the matter of paying for the wedding. And that's not a small matter. The average cost of a wedding in the United States is expected to be around $26,000 in 2015, according to Shane McMurray, CEO of The Wedding Report, a research company that studies trends in the wedding industry. That's up about $2,000 from 2014.

"Couples will probably spend a little more than they did this year because the economy looks better with more money to spend," McMurray said. "And when people have more money they tend to go a little bit extra" with their wedding expenses.

And in certain parts of the country, that figure can go much higher. For instance, in 2013, couples in the New York City area paid the most to get hitched. Newlyweds in Manhattan paid on average the most in the U.S. at around $87,000, according to The Knot, with Long Island being the second most expensive wedding market at an average cost of $57,343. Outside of New York City metro area, other expensive wedding sites include Chicago, Santa Barbara, California, and Rhode Island

While the sticker price is expected to grow next year, the average guest list is not. The number of guests for a wedding is expected to remain around 135 people on average, in part because more couples are paying for the wedding themselves, McMurray said. As a result, more soon-to-be-newlyweds choose to spend on things that are more personal to them, thus cutting back on the number of people they invite.

And as for the actual number of people getting married? That's expected to remain flat. McMurray said he expects between 2.1 million and 2.2 million people will tie the knot next year, about the same amount as 2014.

Read MoreWays to Cut Wedding Costs Without Looking Cheap

Two factors could help increase demand in the wedding industry, though. For starters, same-sex marriage became legal in many more states recently, boosting the number of eligible couples, McMurray said. In the United States, there are an estimated 605,472 same-sex households, of which 168,092 couples are married, according to 2011 American Community Survey from the Census Bureau.

That number is likely to grow in 2015. Currently, same-sex marriage is legal in 35 states and the District of Columbia, but that number could grow to 36 soon. A stay on a court ruling in Florida ends on Jan. 5, and if it's allowed to run out, gay marriages will commence there as well.

Plus, there's a strong chance that the Supreme Court will revisit marriage equality and decide on whether the remaining bans are constitutional. All of this means that many more happy LGBT couples could walk down the aisle next year.

"You'll see an uptick from that because of the demand that's been pent up over the years," McMurray told CNBC. "But that's going to level out in the normal ranges as these couples finally get a chance to get married and start a family."

How people spend their budget may change as well. As the price of oil drops—to a 5 1/2 year lows this week—so does the cost of catering and travel. But McMurray said couples are likely to spend that savings somewhere else, instead of banking it.

"You'll probably see people spending more on the reception and the actual party," McMurray said, adding that some couples may also choose far-away locations for their nuptials if prices remain low. Although, as figures show, decreased oil prices don't always equate to cheap plane tickets.

Read MoreCheap oil: Better for airline passengers or shareholders?

Of course, McMurray said that couples planning their weddings now shouldn't bank on prices to stay low. To hedge against this, he advised caution in gauging the prices of the parts of a wedding.

Budgeting for the big day

There are still plenty of other ways to save on a wedding next year.

When it comes to setting a wedding budget, industry experts recommend choosing a destination and a date first, since where and when you get married will affect everything from travel plans to floral arrangements, which can all factor into the final price. The venue and menu also account for the largest portion of the budget—generally, about 40 to 50 percent, according to Washington state-based wedding planner Jennifer Taylor.

Note that in 2015, certain dates are expected to be quite popular. Both Valentine's Day and Independence Day fall on Saturdays, not only making them high-demand days for nuptials but also expensive propositions for interested couples, according to Sarah Zlotnick, an editor at the popular wedding destination site weddingwire.com. (Also remember that Valentine's Day is already a very popular day for florists, meaning those bouquets and centerpieces will not only see price increases but also delivery delays, Zlotnick added.)

But keep in mind that wedding venues that are typically considered more expensive may actually provide the best value overall. Hotel banquet halls are often all-inclusive, which can end up being less expensive than if the couple arranged all of the catering and decor themselves for a less traditional venue. For extra discounts, consider attending bridal shows and trunk shows, which can offer couples discounts on the vendors they choose.

Even destination weddings can be cheaper than you think. For instance, in Maine, the average cost was less than $30,000, according to The Knot. Plus, destination weddings often entail fewer guests and can occur during a weekday, further driving down the cost.

Read MoreA lavish wedding and ring may increase chances of divorce

"You don't need to go to the Caribbean," said Zlotnick.

But even if you're planning to stay close to home for your wedding, it's easy to save on a venue. Choosing a date that's not during peak wedding season, May through October, can let you find cheaper rates.

Choosing an indoor wedding, as more couples have been in recent years, can also save money. In particular, you'd be able to forgo the costs for tents, tables and chairs associated with an outdoor wedding.

Of course, another big expense for many couples is their clothing.

Zlotnick suggested that brides take advantage of increased competition in the bridal design industry when it comes to choosing dresses. Even mainstream fashion labels like J. Crew and Ann Taylor have begun to enter the fray, she said, giving women more choices. "If you're willing to be a little less traditional, you can get a dress for $600," she said.

Men, too, are benefiting from more choices in formal wear for their weddings. An increasing number of grooms are choosing to eschew the typical black-and-white tuxedo for less formal suits in a variety of colors, particularly shades of blue.

Outside of the venue, food and clothing, how couples decide to spend is very much up to their personal preferences.

"Everything else is going to be based on what the bride and groom are excited about," said Taylor, owner and principal planner of Taylor'd Events.

If a couple would prefer to save on flowers, for instance, one major tip is to choose flowers that are in season or use more greenery. Forget tulips if you're not getting married in the spring.

Taylor also advises couples to account for taxes and tips when planning their budget, as well as setting up a "slush fund" for unexpected expenses.

The number one suggestion Zlotnick had to help couples save money and stay on trend when it comes to their wedding was to hire planner. While wedding planners don't always come cheap, they can help the whole process go smoother.

"Wedding planners are worth it, especially for larger celebrations," Zlotnick said. "They'll typically help you secure discounts and will be better at sticking to your budget than you likely could be."

Another area where Zlotnick said many couples may choose to spend more money is photography. With more newlyweds choosing to share their wedding photos on social media, there's a higher premium being put on choosing a good wedding photographer. And in-demand photographers are more talented than ever, she said, adding to their price and popularity.

Overall, though, Zlotnick advised couples to be pragmatic about their wedding day. For many, it's a once-in-a-lifetime experience and deserves appropriate celebration.

"In many ways it absolutely makes more sense to save the money you might have spent on monogrammed cocktail napkins for a down payment on a home," she said. "But never completely eschew a celebration. … It deserves a break from your normal routine and at least a few hours to commemorate it."