Our area is different (in more ways than one) For the whole county we probably have 3 or 4 families that go to more than one jackpot out of the 60 to 80 beef projects at our fair. Most jackpots are at least 300 plus miles away, so it is a bit costly. There are a few FFA teams that go to one show "Western Bonanza" and that is it. Most kids are in it for the county fair and trying to make some money, now our average price was $3.50 a pound last year so most made some money. I would guess that the range of $ spent for our area is $1000 to $4000 for an animal (the families that spent big $ are gone now) with the grand bringing over $10 a pound every year. The kids who jackpot also have better steers for the same $ as the kids who don't. The breeders they work with help them out since they know they will put in the work and represent they breeder in a positive way.
The kids that go to the jackpots are usually the ones near the top each year, they buy better calves, work with them more and tend to be better showmen (more practice). My boys paid for their calves, they started with commercial calves bought with money they made from their showpigs, I may have paid for their feed up front the first few years but after they sold their animal they reimbursed me. We did not count the cost of jackpots towards their project, like Xbar stated that was the hobby part, we spent time together, met a lot of nice people, and they learned a lot.
As far as a lease on an animal, If you have a kid you want to help, there are a few ways I see to do it, For steers: give them an animal out right and just right it off. Have them work off the cost off a animal (market price) or supply the animal, the feed and when their done take it back and either sell it or eat it. (I would give them a few hundred bucks at the end). The heifer deal has pretty much been discussed enough, I just have one question, if all they want to do is show, why not just let them show in the commercial division (non papered) they get to show an animal, you get to keep the papers on it?