Mate a
Wilderness Tactical "original instructors belt" ($34.95) with a
Blackhawk CQC belt holster with SERPA technology ($44.5) and you'll have one of the best rigs possible at a total cost of $90.00 plus shipping. There are imitations, knockoffs, and lookalikes of both. Stay with the originals: they work, and at these prices it would be stupid to get less than the best. There are other great combinations of belt and holster, of course, but this combination is first rate, no compromise, real professional system at the least possible price.
If I were a betting man and you were a complete innocent I would wager that all or nearly all of your instructors will be wearing a Wilderness original instructors belt, and I would win that bet.
The Blackhawk SERPAs are not so widespread, I think, but I haven't seen anything else like them for retention. Paddle holsters are wonderful things except for carrying guns. Anyone who really wants your gun
will walk away with it and half the paddle holster, which will leave you feeling rather silly or seriously dead. These Blackhawks are model-specific (you must match the holster to the specific model of gun), and even so they're rather fussy about some things (the Model 1911 version, for example, doesn't work with an Ed Brown Kobra Carry because its slide release causes a hangup), so check with Blackhawk to make sure before you buy.
Otherwise I suggest a
Lou Alessi CQC/S (close quarters covert with snaps): it's one of the best leather belt holsters I've found. It's $90 plus shipping.