[kube-system]

You can get a brother QL series label printer for around $100 or less that will print the narrow format 7” postage labels. eBay supports this format with USPS and you also get a good discount through them. I don’t think FedEx or UPS support this format, but I rarely ship with them.

[formerly_proven]

Brother has some free software to design label templates which you can then upload to QL printers. Then you can use their control language over TCP to print labels filling the fields you defined in the template with data; the printer can even generate a large number of barcodes this way. The barcodes even work at pretty small sizes, much smaller than if you were generating graphic barcodes and sending them as bitmaps to the printer. Probably because the rasterization of the barcodes is optimized by the printer for the printer.

The software is janky and their protocol is unidirectional (no way to tell if it printed a given label or ran out of paper, so you have to account for that in your software), but it's very easy to get it to work and when it works it really works. And it's pretty much unbeatable for cost.