FastPasses are free to anyone with a WDW them park ticket. When you can book the FP+ is dependent on where you are staying. The only "paid" FP+ are the private VIP tours where the guides basically act as a human FP+ and the 3 extra FP+ you can purchase if you are staying CL at a WDW or in select rooms at Swan/Dolphin. Otherwise, you cannot purchase FP+ no matter how insistent your friend is.
As PP pointed out, it sounds like your friend may be referring to the Universal Express Pass which is, essentially, a "fast pass" that you can purchase in addition to your theme park ticket. There are some people who think Universal is part of WDW, so, your friend might just be confused.