Wanna do BC but how to tell mom/set it up?!?

Ive been having sex dreams going south because God forbid I have unprotected not real sex in my dreams πŸ˜‘. Like I'll spend the whole dream running around horny but too scared to get pregnant. So I got the screaming message from my subconscious: GET ON BC ALREADY!!! I've already discussed the subject with my mom but the #1 thing that's been hanging me up is which one to choose, what's available/affordable in my area, and most importantly: HOW DO I SET IT UP? I'm 21 years old and have been with my SO for 6 and a half years. I WANNA DO IT with them and it's about time because I'm finally ready and comfortable.