I know of about 15 or 20 digicipher (Not to be confused with FTA DVB) channels that you can receive free with a 920/922. The include numerous PBS, Bloomberg, Varsity TV/Canada, DMX audio (50+) and too many to name. Unlike DVB FTA you must subscribe to at least one C band service to unlock the receiver for the free channels. The best way to find the free NTSC analogue/Videocipher/Digicipher free channels that you can receive with your GI receiver is to check out Lyngsat (hope I spelled it right!). Good luck!
I am not sure where you got having to subscribe to programming to get the free stuff in DC II, but that is untrue. You need to get the receiver authorized is all. I dont have a subscription to anything on my 4tdv and I get all the free channels. Just call NPS and have them authorize the receiver. That is all. Many people have thrown this around that you have purchase programming and that is just untrue.