Pricing Guideline for CharsiFood

Is there a guideline for pricing items based on their scores on D2CharsiFood.com?

Thanks.

That is impossible.
The price of an item change all the time.
There are too many factors that affect the price of an item: when you sell your item (early or late on ladder), how rich is the buyer, how many buyers want it, how long have you been selling it, any modification from Blizz and so on.
CharsiFood is just a source of reference. It is not always accurate.