Yes, even though it's just a few cents most of the time, that does add up! While I was running Incubus Tales, I pretty much used Project Wonderful to offset its own costs. With the help of a couple of friends, I was able to juggle ads and ad costs so that after the first month or two, I never really had to pay for ads again due to what I made from hosting ads! A very good arrangement, I think.
@juliabax The site will probably seem pretty overwhelming at first, but just separate it out and take it a little at a time. I have every confidence in your ability. Mainly because I am godawful at this sort of thing and even I learned at least enough to understand and make/host some ads! You can do it! Just take all the time you need to.