Cheapest way is to get it pulled. No suffering from there, but depends on if you you need the molar......I had several backteeth pulled because I still had my wisdom teeth. I basically made room for my wisdom teeth to come in. Just know that if you have a gap, dont eat hard stuff on that side or you will jab the shit out of your gums not thinking about it, done it a time or two myself. I had one pulled and have a slight gap, if nothing else, just get a bridge or implant later when you can afford it.
Only other option is loan to get root canal/crown. Unless you have insurance that will cover, a good crown will be expensive. I say get it pulled so you aint suffering anymore. Several years back I had to pay 1400 in total, with insurance covering half, so would have been 2800 in all for a root canal and gold crown, went gold because the dentist said being one of my grinding teeth the other crown would be replaced because it would break, gold being stronger.
So i honestly don't know your situation, but if you dont get it taken care of soon you will be very prone to infection and will lose the tooth anyway.