I completely understand. I have had to postpone a neutering before because of lack of funds. People get an attitude, and ask "if you can't afford __________, than how can you afford a pet in general?" It's that initial spending, that lump sum of money. In the long run feed and hay add up way cost more, but in the short run sometimes the $100+ at a time hits hard.
My vet does a payment plan for me. They allow me to pay over 3 months -- and because I have earned credit with them even longer -- as long as I need, interest free. I put a ferret through $1000 of surgery on a part time income because of that ability. Many vets are strict, but many will work with you! There are so many things I couldn't afford if I didn't have help from my vet.
Unfortunately if $90 is a lot to you right now, how do you expect to take care of babies? In this economy, placing them is hard, meaning you may have to keep them for awhile -- maybe for good. Feed costs will go up significantly. You will need cages to house them all separately. What if you can't afford to feed them all? What if no one wants them? What if that happens and you honestly want to take care of them all but you can't and the only ways out are death or abandonment? Even if people DO want them, you still should keep them for at least two months before re-homing. What if an emergency happens? If the doe can't give birth, she will require a C-section - which in an EV could be easily $1000+. If you can't afford it, he and her babies would all die a horrid death. It's not super likely, but it's certainly not hugely unlikely. Breeding takes preparedness.
It's hard sometimes to think in what if's. I am not saying that ill-prepared breeding always ends in tragedy, I was just giving you some points to think about. It just seems that breeding this pair is not in the best interest of you or your buns.
I would talk to your boyfriend. The male in the picture looked young -- it's possible he hasn't bred to her yet. I would separate them for sure until you can afford to have one fixed.
