$100 charging tesla at apartment

So i just ordered a M3 standard range plus and i live in an apartment building. My apartment building garage has EV parking spots that has 100 amp circuit breakers connected to every parking spot. I’ll be getting charged an extra $100 to change to an EV parking spot and the $100 includes the energy used to charge the car throughout the month so basically it’s a $100 flat rate even if i used more than $100 worth of electricity. I was wondering is this a good deal or not and would it be cheaper to supercharge?