Hello and welcome. Don't worry about your learning curve. We've all gone through it. As to the P1, I have one of them and like it quite a bit. The price sounds about right. Used guns are kind of like used cars, in that the better they're taken care of, the better they are. Until you've got one in hand and can look at it, you're depending on the honesty and care of the previous owner. While most of them will be just fine, you will run into one from time to time that isn't what it was represented as.
Look at the record (if it's a CGN offering, click on the "trader rating" number in parentheses under the username) of the seller. Until you have the gun, that's about the best guide. Ask questions such as, Does it function well? When was it last shot? Any cracks or damage to the frame and slider? What kind of shooting was it used for? How many rounds? Heavy loads (P1s without the hexagonal cross pin have had problems when lots of heavy loads were used)? Any parts replaced? Why is it being sold? Any surface pitting or in the barrel? Are there signs of refinishing (stamped letter/number combinations are blurred or indistinct)? You should be given clear answers to questions like these.
As I wrote above, I like the one I've owned for several years; most of the deals are straightforward; don't hesitate to ask questions. There are plenty of people here who would be more than happy to help with any question you post ("pistols and revolvers" section). Enjoy the site.
