You can pay now are you can pay later!!! Like Charlie said, no you don't but trust me the $200.00 or so you spend on a SIM will pay for it self. This is even truer in the early stage of learning because it's not if you crash but how many times you will crash.

It's not as important if you plan to start with a FP but with a CP where every crash will cost you something and time to rebuild.

Tony