Are there any really good photo editing websites? for free? or free trials?

ive tried picnik! and yes i love it but.. i want to know more sites. ive looked at google, but nothing is really what im looking for. I want to be able to take like two photos and photoshop them together like take an object out of one picture and put it in another picture.. if that makes sense. and so i was wondering if theres any good photo editing sites that are free where you can do that.. or if you simply have to buy one to do that, if so what ones would be good to buy besides photoshop cause i heard that's like 99$ ..waaay to much for what i want to spend sorry. so if you have any helpful comments..please share! THANKS:)