Comps
Does anyone have a good reliable formula for doing comps?
I match up beds baths, basement, garage and broadly GLA (+/-100sq ft) rather than # of rooms ...then look for a comparable lot size.
I am finding it hard as there seems to be quite a range of prices in MA. If I get the wrong end .....I either pay too much and cant sell or offer too little and lose the deal. Aim low to be conservative is clearly safer but I would like to do a deal this year 
This is an art I think but wish it were a science!
JK
Add and subtract a value for the differences from each one. Each difference is a small part of the comp but adds up or subtracts from value bigtime. Also 100 sq ft could cost 9200 dollars or 2400 dollars, you have to know the QUALITY of the build. How old the house is, neighborhood, WHAT TYPE OF SALE. Age of systems in home, roof etc appliances. These are all used to get at a true comparison price. TYPE OF LOAN.
Sounds like you need MLS access to "solds" for this?
Or are there any other ways to get it?
JK
You could try http://www.electronicappraiser.com/products. The reports are pretty cheap. I have not personally used this site yet, but it came recommended to me this past week. The sample reports look good. If anyone has used this site please say if you have had a good or bad experience with it.
You would have to dish out 4k at closing then (the diff between 100 and the 96) but you would get a note for 24k if you did it the way you mentioned. Yes the original would get paid off with a new loan, no wrap around would be created through a mortgage broker.
Thanks for your information. I was wondering about that. So if the property sold for 130
80% would be 104
I would get 4 at closing. Do most people structure deals this way with mortgage brokers or is there a different way I am not seeing.
A couple of things to keep in mind. The property has to appraise at the 130k amount. It has to be a loan program that will allow 100% CLTV. And the buyer has to qualify to come in with nothing down.