While it is true that some areas have few enough houses or unique enough designs that direct comps do not exist, the idea that there is no real discernible market value (which is the implication of your post) does not hold water.
Often one has to use other properties that do not match exactly. For example there might be another sale that was similar but had a much larger lot. Using other properties in the area can tell you how much a lot offsets value. This is not magic. Its how appraisers do it. They are generally better at it (though not always) but an agent should be able to give you some idea of value through other sales and offset values of features.
I don’t know the whole situation here (your post was somewhat vague) but I would really reconsider the agent’s value as a professional if they are not giving you some idea of the market value.
Maybe you need a better agent. In this case “better” might mean more experienced, smarter, or just somewhat more familiar with this area.
Maybe you need to ask better questions. It might be that direct comps are non-existent and you don’t care for your agents suggestion of market value. Again not clear from your post.
Additionally, can you explain the relevance of foreclosure sale prices? Who owns the property (eg: Joe Schmoe or Bank of America) has a somewhat limited effect on market value.
