My bike's rear wheel keeps on popping all the time. What should I do?

I have replaced my bike's rear tube in the rear wheel 5 times. I bought the bike for $100 and have spent $50 trying to repair. After the tube is replaced the wheel pops again after a day whether it is used or not. Can someone please tell me what the problem is with the bike and how much will it cost me to fix? Any help will be appreciated.

before you put another tube in, take the tire completely off and rub your hand on the inside of the tire. there could be a small piece of glass, thorn, or rock lodged in it causing your tube to keep bursting. if that is o.k. then check the inside of the wheel it self. there could be a spoke coming inside the rim or a burr that is popping the tube

Make sure the inside of your tyre is clean as is the rim tape on the inside of your wheel rim.

If you've spent 150$, you might as well buy a new, better bike.

your rims could be causing that to but i would take it to a shop and see what they say