You can indeed buy your own Dish receivers, install them yourself, and have them activated for free and w/o additional commitment. Of course any Dish receiver you buy better not be a leased receiver, or you have been sold stolen merchandise and Dish won't activate. You should also get the R00 number from the seller and check with Dish to insure that the account it was on doesn't carry any unpaid balance with Dish, or again they won't activate it.
All additional receivers (beyond the first) carry an additional receiver fee. If you successfully install your 722 and activate, it will become your primary receiver and your 222 will then cost $14/mo. Additionally, any DVR on your Dish account will come with a $7 account-level charge. Unless it's a Hopper or 922 in which case it's more. (Forget the cost myself since I have neither of those receivers.)
IMHO you should have gone with a Hopper to begin with, along with two Joeys, and have HD in 3 locations.