If I had to pay every site I find usefull, man, I would be really poor.

If you have a site that is usefull to a lot of people - than you have to pay the bills. If you have an unusefull site - take it off the net. You either provide a site and deliever a service or you don't. Donationware / Beer-ware was never intended to pay monthly costs for a simple reason - it' not suited.