Now you can earn credits by viewing other people’s ads on TheFreeAdForum.com . Then you can use the credits to purchase ad upgrades to make YOUR ads Premium. As a bonus the ads you are viewing are the other Premium ads.
So if you upgrade your ads to Premium, your ads will be displayed in the credits viewer as well. This will give you even more exposure to your ads. You never have to pay for the upgrades. You just need to view some ads, get some credits, then use some credits from you wallet to pay for upgrades.
Here are all the websites where you can view ads for credits.