If they have the same part number, just use an Aggregate Query

Group by the part number, select MIN for the price. That will give you the lowest cost, then use a dlookup expression to tell you what vendor has that price.

Access Expert 7 deals with products from multiple vendors (suppliers).

Adam;

Unfortionatly item numbers are not the same.  Each supplier has there own item number.  I have set up queries to filter each supplier and products but, I cannot figure out how to compare two suppliers in a query or a report.

Kevin -
The vendor PartID can be different as long is your partID is the same for that part.

For instance Vendor 1 might have SG1 for a Seagate 1tb hard drive
Vendor 2 might have 1tSEA for the same drive.

As long as your part number - say HD001 is the same for both it should show up properly.  I'm pretty sure that is discussed in the video that Kevin gave you above.