The computer is nonfunctional, and in an unknown condition. It looks like it has had some work done to its motherboard, but the person performing the repair was unsuccessful. This means that there are lots of potential problems that you have no way of knowing about. Additionally, similar computers regularly sell for much less money. I think I have seen fully recapped and working SE/30s sell for $300 or less on eBay. This particular seller might not budge on the price, but I'm sure if you keep an eye out, a better deal will eventually come your way. In the end, a computer is worth as much as you are willing to pay. Personally, I would not pay close to that much money for that machine, though.
It took me almost two years of regularly browsing classified ads, but I purchased my SE/30 (with an Ethernet card) for only $30. The key is to find someone who cares more about getting rid of the computer than making lots of money off of it. There are always some listings to ignore -for example, someone locally is selling a 2007 MacBook that was cut in half with a saw.