I paid $1600 for a 2007 People S 250 with 3400 miles. I'm in Central PA. It doesn't sound like a bad deal, you may even get the price down, being that winter is coming soon.
There was a B&H 250 on CL (Philly) for $1800.
Considering there are many new 125's that can be had for $1800-$2000, I'd offer more like $1200.
Also, find out if the CVT belt has been changed, because at that mileage, it will soon.