I need help PLEASE!!!!?

I know this question doesn't normally go out for pregnancy, but beings that im pregnant and the only ones who can sympathize are my peer preggers out there, i'm callin out for some help. Right now, my boyfriend and i are sleeping on a single mattress...TOGETHER!!! like i said before, i'm pregnant, and hes not so small himself, so we need a new mattress and FAST. I just cant afford anything too expensive right now because this pregnancy (as happy as i am about it) was completely unexpected. So any ideas? I'd really like to not get a used one, cause thats just not sanitary. Please no rude comments. Thanks for your help