Prepaid sims

I have a current normal plan with tmobile - but my phone is scheduled to be turned off today and I do not have the funds to pay it and they wont extend my payment plan . 

I was just going to switch carriers but im not sure if that is the best idea either . 

I was thinking of buying a prepaid tmobile sim car and swithcing out my current sims and using the prepaid option till i can pay off my balance . 

this would give me a new number correct ? would this even work as a temporary thing ?