It is comments like dustinwill's that make me shake my head. People that think they know it all and don't - and spout off opinion's like they do.
Listen, there are some bad Realtors out there. Some that don't earn their commission. No one is saying that you should hire an incompetent Realtor. I hate Realtors and I am one. My main profession is appraising real estate. As I mentioned before, there is no possible way you can have enough information to buy that home unless you have comparable sales data. The only way to get that is from the MLS. The only way to get it from the MLS is to get it from a member of the MLS. Period. Realtors and appraisers are members - that's where you need to get this info.
Once you have this data, don't make the mistake of using price per foot. This is a fool's way of evaluating the home. It may work in cookie cutter developments with very small differences between the homes. But price per sf can be skewed tremendously by differences in the size of the home, lot value/size/view, improvements such as a swimming pool, etc. Many licensed and experienced Realtors don't even know how to properly evaluate homes and use this method.
You can call a local appraiser and ask them to take a look at it for you - on a consulting basis only. Get them to run some comps, take a look at them and give you some advice. They can do this for probably less than $100. If they give a value, then they have to create a file and write a report and then it gets expensive. But if you just get them to provide some comps and give you some direction - it is money well spent. Try to find an appraiser that is a member of the Appraisal Institute. You can go to their website www.appraisalinstitute.org and find one near you.
Also, get a home inspection. I don't care how much you think you know about the property and its condition, you need to have it evaluated by someone that knows what they are doing. You can use that report to compel the owner to make repairs.
I am not trying to be a jerk, just trying to help a fellow Ag and first time homebuyer. Do your homework and do NOT trust the seller. Ever.