I don’t have a link but I got something around that price or maybe a few $ mroe at DX. I got something that would work in my Surefire 6P with RCR123’s.
I think mine was around $5. It looks nice however.
I would recommend you to get one of the 7.2V drop ins instead. Better output, whiter tint and better beam pattern. I'm using an Ultrafire G90 drop in that came with a Superfire host (awful quality) bought on DX.
I'm using orange Ultrafire 18350 batteries in this light. If memory serves me right they are bout 800mAh and the bulb draws about 1,3 amps, so the math says a bit over 30 min runtime. That's not much considering the output, at least when you compare a LED flashlight. But the tint makes it worth it, at least to me.
In that case I guess that's about the best you can find. Sure, Lumens Factory have some high powered bulbs made to be used with one battery but they would set you back about $17 and I guess that's not what you're looking for. :)
Just don't expect to much out of that bulb, it's nothing like what you could get out of a 10W led like the XM-L, and to be honest it doesn't show what incans actually are capable of doing when driven hard. Incans don't get fun until you get up to at least 7V...
Another thing, if you don't like the beam profile you can adjust it by unscrewing the bulb a turn or two.
EDIT: eg1977 beat me to it about the Lumens Factory bulbs.
I use a 7.4v 15w drop in I once got from DX and drive it with two LiFePO4 18650 batteries with 7.4V max in total. Well it doesn’t give that much light you’d expect from a 15 w light source but it is a decent power light gives about the light of a 1A driven XPG R5. The color is much better of course, and you can adjust the reflector for distance or more flood, marginally.
What I like most about incans is that by adding a 28mm lens to the front you can actually write on plastics. It takes just 3 seconds to penetrate a CD shell.
I have a 12volt xenon it's pretty cool for what it is. I love the tint it's fairly bright but run time is horrible. I guess I like it for sentimental reasons like an old pickup truck. I need to stick it behind an aspherical and make it into a cigarette lighter so I have a use for it.