I want to get a mountain bike, and I'm 6'6 about 215lbs. I'm new to the whole size thing. I've only ridden bikes from Walmart. I've seen bikes that say XL and XXL frames and then others that say numbers in inches. Can anyone give me some advice on about what size I need. I don't want to spend a fortune either 3 to 6oo. Any help would be appreciated.