McKenna Brothers are about the only commercial public transport information system provider to still print destination blinds in the UK, but there are others about.
Modern ones are just a large roll of paper, similar to lining wallpaper, with the destinations printed on in black and day-glo yellow ink. The amount of ink they take, and the "specialist" day-glo yellow is what often drives up the price of them, along with covering the cost of the large printers and graphics software they use. With them being made like this, specialist graphics companies in your local area might be able to make them for you at a lower cost.