You have forgotten to add compare operator like = or LIKE after Quantity and Price.
Change required in following code block-
bs.Filter = "Barcode LIKE '" & txtBar.Text & "*' or ItemName LIKE '" & txtBar.Text & "*' or ItemDescription '" & txtBar.Text & "*' or Quantity '" & txtBar.Text & "*'or Price '" & txtBar.Text & "*';"
Hope, it helps :)