
To be fair most of the champ shows don't charge for parking themselves, but the charge is down to the site owners, and quite a few who own their own sites don't charge parking at all.
A few charge for parking and no entrance fee in order that legally docked dogs can compete, as the law States that dogs docked after the cut off period (pardon the pun) Cannot be shown where the public pay an entrance fee.
A lot of other types of shows charge a lot more than any dog show.