The fee per month depends on how many months you pay for at a time. If you pay for 12 mo., it's closer to 10$ a month. If you pay for one at a time, it's closer to 15$ a month.
SWG is good if you play a lot, I think. All MMO's out there right now are basically the same thing, though. SWG isnt bad at all, but, its not the best, either. It all depends on what kind of gameplay you're in to. Even though, like I said, they are all run around, kill things, do quests, get experience or skill points, ect. They all pretty much have their own approach.
SWG doesnt like separating the hardcore gamers from the people who just want to play a little bit, so they did away with the "level" system. It really... Doesnt do much, and I prefer a level system myself. If you play a lot, you should be rewarded, goddamnit. Anyways, you can do tons of stuff in SWG, you dont just have to fight. You can be an entertainer or a crafter if you want.
Shadowbane is probably the best if you like PVP (player versus player). Its a ton of free-pvp and guild-v-guild.
World of Warcraft seems promising... I hope.
If you want to know more about MMORPGs (Ive played nearly all of them), feel free to message me in any way shape or form.