Yes, there is a charge ($100) when you get Global Entry which includes TSEPre, and they assign you a KTN.
When DW and I went on a Med cruise five years ago, we got TSAPre for free in one direction but not in the other, which seemed curiously random. I didn't think too much of it though, until I went on a tour of Israel a couple of years ago. On the way back, we transited through Toronto where we went through both Canadian and US Customs (CPB). A few of the tour group members had Global Entry and sailed right through CPB. Even those who didn't have GE (the majority of the group) got through fairly quickly.
I, OTOH, got randomly selected for extensive screening and questioning (starting by having to wait in a loooong line with foreign passport holders), which delayed me by about an hour and 15 minutes, long after the whole rest of the group had passed through, had lunch and settled in at the gate. I determined right then that I would get GE before my next international trip. No more of that nonsense.
Had my interview and got approved two days ago.