There isn’t a direct way to do this with SambaPOS. You will need a barcode printer to print decent quality labels, although it’s still possible using a normal laser / inkjet printer but will be less flexible. Most barcode label printers come with some software bundled, and depending on your needs, you can just use that software to print barcodes. You might also be able to connect to the MSSQL database of SambaPOS from this software and pull in some product details for the labels. Using the specific software will definitely give you the best results with regard to layout of the labels.
Now, with regard to getting something working from within SambaPOS, there was a post before (I’ve linked below) that had a method of printing a label from the POS screen. It generally meant selecting the item on the ticket then pressing a button to print. There is definitely another more in-depth topic about this on the forum but I can’t find it!
That is one way to do it anyway, for sure there are other approaches but it really depends on your needs - like how many labels you need to print, when you need to print, etc.
Your next issue you will reach is getting layout in the printer template for the labels - most barcode label printers don’t support the ESC/POS language (like receipt printers use) therefore you need to use the Raw Printer and in your printer template, write the exact commands to print the layout depending on the command language used by the printer (typically some form of the TSPL language). If you search on forum there are some others have some examples for printing in this format but it varies depending on your actual printer.
Definitely printing on 3 column labels is going to be more tricky than single labels per line.
The labels you mention for the shelves are called shelf edge labels typically. Depending on your store configuration, if you have shelf edges that can hold a paper “ticket” in place (like in supermarkets) you will find it more convenient to use paper instead of sticky label. And this also simplifies printing from SambaPOS because you could in theory print the shelf edge labels using your thermal receipt printer - layout template will be more easy.
On a side note, I do love Tesco’s promotion - 52p each or 2 for £1.70… I’ll take 2 for £1.04 thanks! (I’m sure promo is across all soft drinks but still…)