I'm looking at taking a trip to Scotland next June and wondered if anyone had advice about renting a car. A quick search on the Avis site shows this would be about 200 pounds for 8 days (for a Fiat 500 class car), which seems not unreasonable, especially given unlimited mileage. We're looking at a loop starting in Glasgow, going up to Tain, and coming back down through Aberdeen and Edinburgh, that will be around 600 miles.

I guess my (starting) questions are what's a reasonable cost, do I need any special license, what should I pessimistically expect to spend on gas?

Carrera 4S that you can rent from Avis (if you have deep wallets and are >30) for your time.