I have some toe... they're not warmers, per se, but they're a neoprene toe cover thing, and I wear them for snowshoeing over Smartwool socks. They works great, and I imagine they'd be good for extra warmth during cycling, too. They were cheap, and are not disposable. Might be worth a look. I think I got them at EMS (Eastern Mountain Sports), so REI would probably have them too.