Buy.com has great bargains for Zune accessories, and they currently have the Zune Premium Earbuds going for $12.24 US. They also have the Round Zune Dock for $14.24 US and AC Adapter for $12.24 US, all great prices. If you’ve never used Google Checkout with Buy.com, you can use that feature and get an additional (1-time) discount of $10.00 US.
Note, that I have the Premium Earbuds for my Zune 80 and I really like them. They fit snuggly inside my ear and it seems to block out any exterior noise. Although I haven’t tested them on an airplane flight, I’m sure they will do much better at blocking out jet noise than my old cheapy “outside” earbuds!