Pretty much any site/program you use can handle a simple GEDCOM file. Though, when you save/export from that other program, be sure you save as a gedcom file. Otherwise, you run the risk of it saving in its native format, which doesn't necessarily mean it will be readable from somewhere else.
Ancestry is the 800 pound gorilla. It's popular because so many people use it, which makes it popular. They love to "nickle and dime" their users, so be prepared for that.
Most libraries give you the ability to search a version of ancestry for free, but it's extremely limited, and you pretty much have to know exactly what you're looking for. General searches are useless.
Depending on your area, you may have other resources available. In my area, there are two family research centers. One is run by the Mormon church. I'm not sure who the other is run by. As I understand it, they both give full free access to pretty much any gen. site out there.