Helmets. If that's the only auction then does the sale of those 130 helmets cover the cost of 500-600 helmets? If there are other auctions then how many additional helmets get sold. Personally, if I was to buy a helmet, which I have no desire to do, I would want a traditional helmet, not some off brand color that doesn't show the traditional VT logo.
Even if they do sell enough to cover the cost, my guess is they would sell close to the same amount of helmets if VT wore the exact same helmet every game. Which means the money & time spent changing helmets comes completely out of the advertising budget as a cost incurred & is no where near a break even expense.

Personally, I think the money could be put to far better use. The players may like the different colors but I bet if you gave the players the option of wearing the same helmet as last game in return for $50 bucks. They would take the cash & the school would come out ahead.