HI!! Just for information for any newbies in the car rental area - Something I learned the hard way!!
When I first booked my $99 + something car with a credit card, I was told they would hold $200 line of credit until I returned the car. Ok, quite understandable, and the 'norm'. Well what I didnt know is when they gave me the double 'free' upgrade, they then tried to hold almost $600 line of credit, which then wrecked havock with my future vacation plans.
It all worked out, but it was a lesson learned, and I thought I'd pass it along for those that may want the info!!