How to price home when selling

[Marilyn A.]

How do you like to price your homes when you are selling? A couple of the books I've read say to double what you paid. I was thinking that would be a good minimum to aim for, but would think you could sometimes make more by pricing near market value.
My plan is to sell on payments, but sell for less for cash.
How do you know market value? Do you use the NADA guide?