You'll probably find that most of these trade-ins were carried a lot and shot a little. Most are mechanically excellent and minor cosmetics can be polished out, especially on a stainless gun.
The model 64 is a great gun - stainless steel version of the model 10, direct decendant of the original "Military & Police" and among the most popular guns in history. With a 4' barrel in .38 and stainless you'll have a great "all-around" gun that can serve you well for a variety of purposes and last to be handed down to your kids some day. $250 is a great price and will only increase in value. (If you ever decide to sell it you'll always be able to get that much or more for it.)
Don't obey those who insist you need a .357 instead of a .38. The .38 is accurate, available in a huge variety of loads and is perfectly capable as a defense round. (And, yes, it's OK to load it with "+P's".) Another great thing about the k-frame Smiths is the large number of grip options available from basic black rubber to beautifully hand-carved exotic woods.
Good luck.
