Ok...
Let's assume on Sheet2 you have a 2 column table of products and prices like this:
<TABLE style="WIDTH: 96pt; BORDER-COLLAPSE: collapse" cellSpacing=0 cellPadding=0 width=128 border=0><COLGROUP><COL style="WIDTH: 48pt" span=2 width=64><TBODY><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-RIGHT: #d4d0c8; BORDER-TOP: #d4d0c8; BORDER-LEFT: #d4d0c8; WIDTH: 48pt; BORDER-BOTTOM: #d4d0c8; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" width=64 height=17>Products</TD><TD style="BORDER-RIGHT: #d4d0c8; BORDER-TOP: #d4d0c8; BORDER-LEFT: #d4d0c8; WIDTH: 48pt; BORDER-BOTTOM: #d4d0c8; BACKGROUND-COLOR: transparent" width=64>Price</TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-RIGHT: #d4d0c8; BORDER-TOP: #d4d0c8; BORDER-LEFT: #d4d0c8; BORDER-BOTTOM: #d4d0c8; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17>product1</TD><TD style="BORDER-RIGHT: #d4d0c8; BORDER-TOP: #d4d0c8; BORDER-LEFT: #d4d0c8; BORDER-BOTTOM: #d4d0c8; BACKGROUND-COLOR: transparent">10 </TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-RIGHT: #d4d0c8; BORDER-TOP: #d4d0c8; BORDER-LEFT: #d4d0c8; BORDER-BOTTOM: #d4d0c8; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17>product2</TD><TD style="BORDER-RIGHT: #d4d0c8; BORDER-TOP: #d4d0c8; BORDER-LEFT: #d4d0c8; BORDER-BOTTOM: #d4d0c8; BACKGROUND-COLOR: transparent">15 </TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-RIGHT: #d4d0c8; BORDER-TOP: #d4d0c8; BORDER-LEFT: #d4d0c8; BORDER-BOTTOM: #d4d0c8; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17>product3</TD><TD style="BORDER-RIGHT: #d4d0c8; BORDER-TOP: #d4d0c8; BORDER-LEFT: #d4d0c8; BORDER-BOTTOM: #d4d0c8; BACKGROUND-COLOR: transparent">17 </TD></TR><TR style="HEIGHT: 12.75pt" height=17><TD style="BORDER-RIGHT: #d4d0c8; BORDER-TOP: #d4d0c8; BORDER-LEFT: #d4d0c8; BORDER-BOTTOM: #d4d0c8; HEIGHT: 12.75pt; BACKGROUND-COLOR: transparent" height=17>product4</TD><TD style="BORDER-RIGHT: #d4d0c8; BORDER-TOP: #d4d0c8; BORDER-LEFT: #d4d0c8; BORDER-BOTTOM: #d4d0c8; BACKGROUND-COLOR: transparent">100 </TD></TR></TBODY></TABLE>
A1:B1 are the column headers and the data is in A2:B5.
Since this table will be updated with new products from time to time we want to create a dynamic range for this table.
Goto the Formulas tab
Defined Names>Define Name
Name: Products
Refers to: =OFFSET(Sheet2!$A$2:$B$2,,,COUNTA(Sheet2!$A$2:$A$100),2)
Use a reasonable end of range $A$100 that allows enough rows for future additions to the table.
OK out
Now, setup the data validation list.
Navigate to Sheet1
Select cell A1
Data Validation
Allow: List
Source: =INDEX(Products,0,1)
OK out
Now, enter this formula in cell B1 to get the price for the product selected from the drop down list in cell A1:
=IF(A1="","",VLOOKUP(A1,Products,2,0))
As you add new products to the table on Sheet2 they will automatically be added to the drop down list.
Just make sure that when you do add new products to the table, you do it so that there are no empty cells between items in the table. You want the table to comprise a solid block of data.