Text Value Used in a Formula

I've run into a stumbling block setting up a template for the Manufacturing Company I work for. I want to assign a numeric value to an item number(text). In this case let me use the example of P61B1 is the item number of a product. The value of the product is 4.67. So it my spreadsheet I would like to beable to just type in the item number, then in the next cell, the quantity, and then in a third cell, the product of the value multiplied by its quanitity.

The problem I'm trying to get around is memorizing all the values for the products. Once the item number is typed in its already assigned a value that can be quantified.

The way I went about this is defining the text "P61B1" as the value of 4.67. Which works, in the formula bar if I type in P61B1*5 i get my formulated value. But what I can't get around, in cell D2 I have the text P61B1 and in cell F2 I have 5 and in cell E2 I want =D2*F2. But for some reason the D2 cell does not read it as P61B1=value of 4.67. I don't completely understand why it doesnt do that, and I guess more frustrating I just want it to work!! Any help or suggestions would be greatly appreciated. Thanks so much!!

Sounds to me that you should make a lookup table and use VLOOKUP. If you post a workbook with some mock up data and examples of what you want to achieve I'll fix it.