Given the options for getting AirPrint working with your existing gear, it's probably not necessary to run out and get a brand-new printer just to enable output from your iOS 4.2-enabled iPhone, iPod touch or iPad. If you actually need a new printer, however, it's worth considering whether one of HP's AirPrint-ready models is suited to your printing lifestyle. For Cyber Monday, HP is offering instant rebates on all the Photosmart inkjets that are qualified for AirPrint use.
While HP's press materials indicate that all of the company's ePrint-capable printers will eventually work with AirPrint, only about 10 printers are ready for iPad printing out of the box or with currently shipping firmware (full list here). Of those, almost all of these are discounted for Cyber Monday, ranging from US$30 off the budget Photosmart D110a (for a total cost of $70) up to $50 off the C510a and $100 off the A910n. All models include free standard shipping for the sale event.
Chances are, if you've got an educational or EPP (employee purchase program) discount, you'll be able to shave a few more dollars off these prices. Our colleague Laura Heller at WalletPop suggests checking price aggregator sites like Fatwallet.com or Dealnews to verify that you're getting the best deal, and make sure that your local office equipment chain (OfficeMax, Staples, etc.) won't beat the price.