At Glenorchy (MTBA Nats round 1) I spoke to a number of riders who were race winners, and therefore awarded the jersey. Many were in dislike of the podium procedures, where they would walk out on to the podium wearing a series leader jersey, therefore covering any sponsors logos. As one rider put it, they support them and put time and money into getting them there, only to be completely ignored when they're shown to support a rider at our highest national level?
In Victoria we've started awarding state champion jerseys again at the conclusion of certain races and series (for XCO it's at the State Champs, for XCE there's no State Champs, so it's the series winner). These will be printed in such a way that transfers are provided to the riders, which can effectively just be ironed on, allowing sponsor logos to be shown on the state champ jersey. We don't place any logos on the state champ jersey - it is purely a white jersey with the navy blue stripes, and that's it.
The idea is that any entry fee will be waived if they wear the state champion jersey at that event (and are the current state champ), and though we would like to see it be mandatory if you win it, it's hard to push as it may be disliked to do so.
Personally, I do not see a $90 cost as a huge budget blow-out.
From next year we're also looking at a plate system, returning to how BMXA have done since the beginning of time.
Perhaps some of these ideas can be pinched if it's an idea you want to follow on with.