Purchase, yes ofcourse… Use it, I haven't got a clue… But do you honestly think the A-team would deny selling something that isn't usable for someone? lol
Definite answer…though I thought I had made myself clear…like clothes,…you must be a premium to designate this room for use. As to whether as a non-premium someone can invite you into this room I do not know.
@Bear: You said it yourself. The one who invites, determines the room. Same as with premium poses, once a non-premium user is invited, he/she can enjoy all the poses of the premium user. It is the same in the new room. And I think it is safe to say that, once purchased, the room stays yours, wether you are premium or not.
I'm with Tight, though I don't know it for safe. I think you can enter the room as long as you choose another one. It might be the same with your clothes: As long as you are wearing them they are not lost.