What is the most accepted method of calculating a carrying value for work in process inventory in a manufacturing environment without job-costing capabilities?
I have tried the following methods:

1. Wholesale (distributor) price times percent complete

2. Retail (list) price, reduced by an estimated margin, times percent complete

3. Wholesale (distributor) price, reduced by an estimated margin, times percent complete

4. Average selling price (wholesale and retail combined), reduced by an estimated margin, times percent complete


Is one of these better than the others, or is there another method that is more acceptable?
Thanks for help offered.
KJW