StockQuery treats input from a Bar Code Scanner just like it treats input from the Keyboard. You basically scan the part number into the part number text field of a StockQuery dialog box with your scanner and proceed as usual.
StockQuery can also import inventory transactions from a file. If the scanner is able to create a text file with scanned product numbers, that file can be imported into StockQuery.
We do not have a specific recommendation for a scanner. Any scanner that can be used in the manner described above should work.