Being polite and asking nicely pays off.
 

I recently rented a minivan at PHL airport. There was a special online and it was the best price for the time period. It took a while for the Budget shuttle to show up (I think every other company passed by 2-3 times), but then two came at the same time. When we finally got to the rental location there was a decent size line and only four people working.

After seeing the available minivans in the lot, I wasn't expecting too much (saw lots of Dodge caravans: base model, and a few Ford minivans). The rep was very nice and I asked if it was possible to get the largest minivan they had since it was going to be full with 7 people. He searched a little and then said he could give me a Toyota Sienna 8passenger minivan, which was one of the largest they had in the class.

I'm 28 and not a minivan type of guy, but Wow, this thing was nice. 8 seater, dual sliding doors (with full power windows), stow and go seats, power everything.

I guess it pays to be nice and it doesn't hurt to ask for "upgrades". This also works well in hotels, along with the $20 "trick".

just out of curiousity, what is the "$20 trick?"

Slipping the hotel clerk 20 dollars and asking if there are any "nicer" rooms available. Basically, bribing the agent.