[Big Kev-O]

I have used and maintained lots of Ingersoll Rand compressors throughout my career and have seen very few failures. The only ones I have seen fail ran continuously 24/7 for at least 10-20 years. I think Grumpy is correct, it looks like the SS4L5 sold at Tractor Supply that is currently priced at $849($921 with sales tax where I live). If it is a SS4L5 $700 is a fair price if it has not been used very much. $600-650 would make happy. Check the condition of the oil on the dipstick and if its pitch black that thing has seen some hours. If you loosen the plug on the bottom of the tank I would expect to see a little rust in the water but not much since it looks fairly new. You won't have a warranty but IR has rebuild kits available should you have a problem.

I don't like black pipe due to rust issues. Cooper is my preference but it's expensive. I would choose schedule 80 PVC over black pipe.