IUDs are great to prevent pregnancy, although they do not prevent STDs.
Sorry about the typo. The phrase is "no hat, no dance."
When you say futile, do you mean you are too fertile to be in a relationship?
Condoms are cheap, and you can make the man buy them. No had, no dance, as they say. Your least expensive bet is him buying and you insisting he use, the condom, and you using a spermicidal foam at the same time. Condoms + foam have a pretty good success rate although it is dependent on you being reliable in saying no to any sex without it.
IUDs are good. Go to Planned Parenthood, they charge on a sliding scale.