trying to match vendor to lowest price

You're working uphill if you try to arrange data like that in Excel.

In the attachment, data is arranged in database fashion. Enter an item number in A2 and see the minimum price and vendor in E2 and D2.

Both E2 and D2 are array formulas, which means that the must be confirmed with Ctrl+Shift+Enter, not just Enter like you're used to. That's what makes the curly braces appear in the formula bar -- you can't type those in directly.

The formulas reference dynamic named ranges that automatically extend down as far as you have entries in column A.