Any cheap printer with disc capability is fine, discs don't require or support high-res printing. "Affordable" usually means: how much does it cost to run? They are all around the same prices, it's the ink that gets you. Also, some have such crappy disc printing software that you are forced to buy software to get a decent result.
HP: Expensive to run, horrible software and driver.
Epson: Mediocre software that is usable but not outstanding, expensive to operate.
Canon: In the USA they must be modded to print discs, and you need to buy a disc tray off
ebay: cost about $25 and 10 min time. Software and driver are the best available, cost to operate is slightly less than Epson.
The Canon IP4500 is just discontinued and cheaper than ever. It will replace any printer you currently use for quality and speed. It's the cheapest Canon model that can print discs.
Bottom line, if you're only printing a couple discs a month, either the Canon or Epson will be relatively cheap to own. If you print a lot of discs, go Canon.