problems with find and replace

I am kinda new to excel and am currently trying to use the program to edit a online product file I have downloaded. The problem I have run into is this:

I have a whole column with shipping weights (1,2,4,ect.).
I have all the pricing that it would cost to ship the products, according to the weight. So I am trying to find and replace, but when I do this one by one, I run into problems. As I replace, old with new, now the new cells are being edited as I try to replace other cells. Is there a formula that i am overlooking that I might use. There are over 1400 products that I am editing, so doing this one by one would be rather time consuming, and hope someone could push me in the right direction here.

thanx. Brad

Brad welcome to ExcelForum!, can you create a dummy workbook (no sensitive or personal data in it) with a sheet for what you have now and a sheet on how you expect it to look?, once you have your sheet you need to zip it and attach it here, that way we will be able to give you the help you need!