Had a similar experience in HOU. Was told by lady at airport desk there was a Jeep that "I would be mich more comfortable in" for only $2 more. This was a Priceline rental, so I politely declined (but not forcefully enough) as I didn't want ANY extra charges. She calls the lot (I guess to see what cars are available), can't get anyone to answer the phone and then mumbles "oh I'll just put you in the jeep anyways." ok, to me that sounds like a free upgrade. I even confirm with the lot agent before i drive off that there are no additional fees here right? - I'm prepaid with Priceline. Of course he just tells me what I want to hear and doesn't really look at my receipt. And nor did I understand it either because I thought the amt on the receipt was confirming the amount I had paid Priceline. (they were also charging me $35 for an extra hour rental because I was an hour early). At any rate, I phoned CS after returning my rental and reluctantly they credited back the extra hour and measly $2 upgrade fee. The lesson I learned here was threefold: be more assertive, understand the est charges on receipt fully before leaving lot, and that the receipt should have said $0.00 - as it was a Priceline rental.