I bought a refurbished bike - for more than the cost of this cruiser from Amazon (damn it!) - but I do feel better about reusing something that was originally thrown away.

No cars are allowed as transportation around the camp ground (except art cars), so you will need a bike. Read very carefully. DO NOT take your good bike to the Playa. It will be destroyed by Playa dust. Buy the cheapest bike you can find with WIDE tires. Many people abandon their bikes at the end of Burning Man (mostly foreign travelers who flew in for the event). If you are going early (the day of opening), there is a place on the way to Burning Man, about 5 miles out, that sells the reclaimed abandoned bikes from last year's Burning Man. They are super deals at about $25-$50. But you are risking it by doing this. You cannot get around easily without some type of transportation. Burning Man is huge, and you often have to commute far out to see all the art.