Barcodes for products I want to wholesale to shops

[Lililly]

Does anyone know how to get a barcode for a product. I am packaging the product at home, and just about to get a part of this printed.
Some shops require barcodes for their till systems, so I would like to sort this now, I have seen them for sale online for £5 each, but I need a few, and wonder if this is money for old rope / ignorant people like me who just don't understand the system (like designers who charge to generate QR codes)
Does anyone have any experience?

Thanks!

Have you had a look at this website?

GS1UK

There may be others, but this seems to be the one most people use/talk about.

I've used Nationwidebarcode.com to allow me to sell my own products on Amazon though I've now learned there is an Amazon coding system for people in my position.

Have your customers specifically asked for items to come ready coded? When I sold to shops they priced and coded them themselves.