Personally I have a modified CueCat barcode scanner (it's important that it's "modified") which I got for less than $10 many years ago.http://cuecats.com/USBProductDetails.aspxhttps://www.ebay.com/bhp/cuecat-usb
When you scan a barcode, it's as if you had typed the barcode with your keyboard. For example, if you have a text editor opened, you'll have the barcode added as text. If you have Coollector opened, the corresponding DVD will be added as owned, nearly instantly. I suppose that many/most/all scanners work the same way, but I can't tell for sure because I've never had another scanner in my hands.
If you want to get a preview of what it looks like, you can copy a barcode into your clipboard (Control + C), then paste it into Coollector (Control + V).