What formula/rule can I use that will automatically match and pull info

I don't know if this exists, but I'm hoping someone can help. I have two excel spreadsheets. One is a list of sales made, the other is a product list that has our cost per product. I'd like to use a formula or something that would match the part numbers on each spreadsheet and pull our cost from the product list and add it into a collumn next to the matching part number. The sales spreadsheet will have the part number multiple times. Is this possible? I figured they would have to be in the same spreadsheet, but seperate tabs. That's as far as I've gotten. Any help would be appreciated. Thanks!