Self-teaching Spanish ?

Ok, so I know english, german, russian and latvian.

Whats a good language to learn ? I was thinking about spanish because thats the most widely spoken language right after english. Cant really think of a more useful language at the moment.

Any good online sites for learning ? I have no access to tutors and dont plan on paying anything. If anyone has learned on their own through free websites or such, please share.

>>3
It's not. However, you'll be instantly part of some sort of cult. All Esperanto speakers form a society of their own.

Plus, it gets easiert to learn Romance languages.