I had a Samsung laser printer which I filled up the cartridges with toner off
ebay. Had no problems with refilling at all, but after a few refils you'll need to buy a new/remanufactered toner cartridge as other parts need replacing too.
I used it mainly for printing the local newsletter, approx 1200 pages a month, toner cost per 1000 prints was approx £5

& the printer itself was under £50. It finally died last month after nearly 3 years, so didn't owe me anything.
After looking at new laser printers, it appears that some now need a chip when the toner is refilled, increasing costs. I've just ordered a HP P1102 which I believe can be refilled by myself without chipping though
