When i saw the OP and saw that price, i was like "OMG, no way!, subscription payments, for a SIM??".
I've read the pages afterward, and i still wouldn't pay $20 to "borrow it for a while".
Having said that, If Scavier came out tomorrow and said "After the next patch, you will be required to pay £6.50 per month to carry on using LFS" I would pay it in a heartbeat.
So, i guess what i'm saying is, it would be best for them if they released a Demo similar to how LFS's Demo is, so we could get a proper taster for free. Then IF it was as good/better than LFS most probably wouldn't mind paying every month.