If you buy the old CodeMasters MoM retail box, you won't have anything at all for they are not valid anymore. So beware! VIP grants you 2 temporary char slots. You are asked to lock out 2 chars on the next login upon ending your VIP time. The MoM expansion itself grants 2 permanent char slots (plus permanent access to Rune-Keeper and Warden classes and the skirmish soldier upgrade). Be advised that this only comes with the expansion and not the quest pack.
even though you will lose access to 2 of your slots when your 30 days is up, you should still create a toon and log onto it so that way if you later decide to open it back up with tp later you will have all of the vip perks on it like gold cap and swift travel.