First Purchase Price Question

Hi, All;

Have looked at some a/c for sale, and have found one I'm interested in.

The bird has not been flown in over two years, and is out of annual.

The owner said that he would have an annual done before quoting me a price;
guess he figures it will be worth more as a result. This was one of those
situations where I noticed a plane that didn't seem to have much use, so I
decided to contact the owner.

So, an annual was scheduled. The A&P (has never seen this a/c before) says
that it needs quite a bit of work. Needs a top overhaul, some brake work,
nose strut rebuilt, and some other lesser items. Otherwise, the airframe is
in good shape; paint fair, but passes the 20' test, needs some carpet and
plastic.

What is usual here for working up a price, realizing that there probably
isn't any typical way of handling the negotiations? At this point, nothing
is signed. The owner is stating that if everything was working fine, it
would be worth "X" dollars, and he is considering the option of selling it
for "X" minus the estimated cost of repairs for the items above.

My thoughts are that since a test flight has not occured, that more things
might crop up, so the price should be decremented some more. Is there any
rule of thumb for these situations? It's a common simple plane, but I'd
really prefer to work with something local at my current airport instead of
continuing to hunt all over the state/country.

Thanks;
Carl