When someone buys their car at the end of a lease can the dealership who handles it charge whatever they want in fees?

I realize on the contract is the residual value, and my contract also states an additional $350 flat fee. I just talked to the dealership and the salesperson mentioned “other” fees. Can they just charge whatever the hell they want? I am not talking about taxes and tags, I mean administrative fees.

The leasing company says the transaction has to be done at the dealership, it can’t just be over the phone or send in a check.