Serioisly? You know what costs $25.00 a day? Going out to eat, buying some coffee and going out to lunch, filling up gasoline in your vehicle. The list can go on and on.
Difference is, this money is an investment in yourself. If you're not willing to invest at LEAST $25.00 a day in yourself, then you've got your priorities backwards.
I used to cry over $25.00 a day too, don't get me wrong. But now I'm spending a minimum of $75.00 a day into ads, per ad.
Spending $5.00 into ads is like urinating in the wind. You're not going to gather any significant data and you're definitely not going to make a return.
If I were you, I'd at least update the daily spend to $10.00 - $20.00 each ad, until you find a winner. (You don't have to run them at 30 days. You can run them for two weeks and then sort through the results)