Quick straight talk question

I'm buying a used HTC Inspire tomorrow for $140.00 and want to know whether i can just use the st sim card or if I have to buy the Nokia E7 from them,and use that one. I don't see the point in buying a $100.00 phone when I can just get the sim for $14.00,all the how-to's say that you need to buy the Nokia but don't say why. Don't know whether straight talk didn't sell the sims when those guides were written,I just need a quick answer before I go ahead and buy the phone tomorrow.


Edit:If this has been answered,mods feel free to lock the thread and pm me the link. I just couldn't find it in my first search

 

Actually i found my answer after looking at the HoFo thread again,feel free to close the thread