We are not millionaires, and we can't afford the prescription flea
treatments like Frontline or Evolution even though we know they work.

Unfortunately, you're going to end up spending more money if you get
the cheaper stuff
1. you'll use it more frequently
2. it just isn't as effective so you'll end up spending money on flea
bombs
3. in a worst case scenario, one of your cats will react to the cheap
stuff and you'll end up with a vet bill.

Frontline is worth the money in the long run.