Swordsman/Knights buying places !

[Belgarath]

Did you get the Mysterious Parcel from the tavernkeeper in Arlania? You can get most units from that, but it's not cheap...
If you did not get it yet, you need to be wearing the Old Boots when you talk to him...(you usually get them in the tutorial dungeon but they are often found later in the game as well...)

[Totoro]

A guy in Merlassar also sells human units.

[Arnyxx]

Yeah the mystery parcel works thanks dude