There are a few variations of the P220, although most likely it's your 'standard' model with alloy frame. I wouldn't buy an alloy frame gun at any price, but that's just me. There's really no way to know if that's a good price, not knowing if it's an all stainless Elite model in good shape, a standard model with or without night sights, or what condition the frame rails are in.
In looking at it, I'd remove the slide to inspect the frame rails for wear--it's a place where poor lubrication/maintenance can result is a lot of galling. As for it being 10 years old, I wouldn't worry about that much as far as non-cosmetics go.
My experience with the P220 is that it's a real pleasure to shoot, extremely reliable and function with no issues using all ammo you can throw at them. I'm sure there are exceptions to the one P220 I've owned.
While it's a big gun, it is a great carry if you can handle the size--the DA/SA trigger can be tuned easily to be as smooth as silk, and the DA weight can be brought down to 4- 4 1/2 lbs with Wolff springs. DA is attractive to some folks because of the high degree of safety provided in high stress situations, and of course in those situations you won't know it's DA or SA.
They do have a relatively high bore axis--about 1/2" higher than the M&P in 45, and it is of course a single stack that feels kind of like a double, even with thin Sig grips.
If you like the P220 and the gun is in good to very good condition I think the price is reasonable. I just sold mine for over $900, but it was the Elite model, in mint condition and had significant customization plus $300 in magazines.
Good luck!
