I didn't even know they made an NSR150, but here's a pretty clean looking bike in Orange County for $5100.
Honda Repsol NSR 150 SP Pro Arm
This motorcycle is currently CA Registered through 2009. There are about 35,000km on the clock (21,750mi).
It was imported originally from Thailand. The bike is in excellent condition with the only major flaw being the dent (pictured below) on the fuel tank.
It is mostly stock with very few modifications, which I listed below. This bike is a two-stroke. And, since it is a 150cc, it is freeway/highway legal. It also features a single swing arm. This is a very rare bike.
Aftermarket parts installed:
Stainless Steel Braided Front Brake Line Grips/Bar ends
Tyga Rear Sets
Tyga Carbon Fiber Exhaust Pipe
I'd try to use the dent in the tank as a bargaining tool to get the price down a bit. But it is a rare find in the states and it has title and tags.