It sure would be nice if there was a rule of thumb to figure out a good offer price. The real truth is that since there is no rule of thumb for pricing, there can be no r.o.t. for offer price either. We are all at the mercy of the comps! Without evaluating what the homes in the subject neighborhood are selling for, you can never know a home's value, or if you are getting a good deal. Hook up with a good buyer's agent who is familiar with the neighborhood in question, and they can guide you in formulating a realistic offer.