318 Price Range?

I am sure this is probably a very vague question but I am in the market for a 318. However, when I look on line they seem to range from 1500 to 3000 or so it seems. What is truly a fair price for a 318 in good working condition? With that what are some of the things to look for that would scare you away from a purchase?
How many hours should I expect to get from this engine before rebuild? The machine I buy will be for minor home use and use on my shooting range... nothing abusive... more an "I want" than "I need." That is why asking for some direction, too easy to make an impulse purchase! Thanks & Keep it Green!!