Donald Trump's campaign is still spending remarkably little

Donald Trump's campaign has proven unconventional at almost every turn. That extends to its spending.

Trump's campaign committee reported $18.5 million in disbursements in July, up from $7.8 million in June, according to a Federal Election Commission report released Saturday. That compares with the roughly $38.2 million spent by his Democratic opponent Hillary Clinton and falls well short of what recent nominees have spent.

The billionaire developer, who has put about $50 million into his own campaign, has run a remarkably cheap operation, even in the general election. Trump has relied on intense news coverage and social media to push his message throughout his campaign, largely shunning traditional advertising channels and some methods of voter outreach.

The Trump campaign only recently placed its first battleground ad buys in Pennsylvania, Florida, North Carolina and Ohio for about $4 million, according to NBC News. The Clinton campaign put up its first general election TV ads more than two months ago and has since spent more than $60 million on them.

It remains to be seen how much Trump's spending will change in August and beyond as his poll numbers flounder in key states. He currently trails Clinton by an average of 5.5 points in recent polls that include the Libertarian Party's Gary Johnson and the Green Party's Jill Stein, according to RealClearPolitics.

A large part of Trump's spending jump in July went to Giles-Parscale, a San Antonio, Texas-based web design and digital marketing firm. Trump's campaign reported nearly $8.4 million in expenses to the firm, about 45 percent of its total, and up from about $1.6 million in June.

However, spending on payroll and ground operations barely budged.

At this point in the race, Trump is spending considerably less than past nominees. In July of 2012, President Barack Obama's campaign spent nearly $59 million, while Mitt Romney's spent almost $33 million.

In July of 2008, Obama's campaign spent more than $57 million, while Sen. John McCain's spent more than $32 million.