Trump has largely used the news media to generate the publicity he needs. Spending on TV ads has been neglible compared to the Clinton camp. However, according to Republican Committee sources, even after spending so little, he’s out of money completely now and will not be able to run TV ads until after he is confirmed as Republican nominee and has access to the cash that comes with that confirmation.
This means that the Clinton campaign can run a serious ad campaign to frame Trump in a negative light over the next two months, and will have free reign to say what they like with little if anything from Trump to counter it. The GOP Convention takes place in July.
One thing Trump can count on though is plenty of free air time from the FOX network, where he even has his own program today, confusingly still called by its old name, the Sean Hannity Show.