Using a data of a field of a table in a field of another table.

[Milon Mahbub]

I have made two table in Ms Access (a) Product Information (b) Sell Information.
"Product Information" Contains those fields.
1. Product ID
2. Product Name
3. Category
4. Purchasing Price
5. In Stock

"Sell Information" Contains those fields.
1. Sell ID
2. Product ID
3. Selling Price

I need to use a field named "Purchasing Price" in Data table "Sell Information".