Generally, having your unit purchase a few sets of Uniforms/Traps from C&C and the like is a great idea. After the event is over, they just turn the kit in. As time progresses and they buy piece by piece, the less they will have to borrow. Spending $500.00 for full kit for loaner (Minus rifle, of course) is decent for any Unit to do and not too burdensome on the company treasury.
My very first event, I wore full loaner gear from C&C and it served its purpose. No "Stitch Nazi's" gave me flack nor did any of the veteran members. They were just happy to see a new face in the hobby and show me the ropes. Since then, I've pretty much bought everything I need for a full impression. I'm just short of having a Shelter Half, Great Coat, and an extra gum blanket. Depending on their income, it is best to save money and borrow kit until they have enough to buy quality gear. Only two items out of my kit are not "Campaigner" Quality so to speak, which is my Frock and Trousers, but even at a Campaigner Event, I was not belittled or anything of the sort. (Which, I know many people fear).
My unit has these three things as "Must Get" first: Hat, Blouse, Footwear. Then build from there slowly but surely.
We all know it is an expensive hobby to start, but once you have everything (Generally 1-3 years to acquire everything), then the only thing you will spend is on Powder, Caps, and unit fees.
(Sorry if this is a bit winded, but I know any advice and tips will help)