Off Topic: selling a product line

FROM : Kimo
DATE : Thu May 08 02:31:43 2008

This is not the usual development question, but this list probably has 
the best people to answer.
Suppose you wrote a cool Mac product, and it's been selling well as 
shareware for years.  Then a larger software development company 
contacts you and says they want to purchase the entire product 
outright, source and all, for a lump sum, no royalties.  And they ask 
"what do you want for it?" How would you ever determine the price? 
Some people have said to estimate at what it brings in over 1 or 2 
years.  Others have said that it shouldn't be a price more than it 
would cost the company to develop the product themselves from 
scratch.  Is there a standard method for determining the cost of a 
product, possibly similar to appraising the price of a house before 
you sell it?

I hope this topic is not too far off-topic.  Thanks for any help.
-Kimo