How do you Appraise Something With No Comparables?

[Anthony R.]

I have a 4 unit that I'm considering letting go to 1031 exchange for something bigger. The problem is, the last person that bought a building similar to mine in this town, was me.... There's nothing like it that's sold or that's on the market in the area. How the heck do I come up with a price? 

I bought it for 90k. I put 20k into it. It now grosses 2200 a month and I net on average 900-1100 a month. The neighborhood is a C or D. 

I estimate that it's worth about 150k but I have no way of proving that with solid data. Is there any way to figure this out without first ordering an $800 appraisal?