Maplins do a 210 lumen led torch (flashlight) for about £25 (3 or 4 "c" cells) I think, other pilot had one last week, just about melted the paint off the aircraft on the walkround it was that bright.
Just got an LED Lenser, 4XAA cells in a cluster shape so short and fat (no jokes now!) V good, not tried it out flying yet.
I've just been using a hillwalking type 3 led headlamp for flying for the last year or so, not really enough light for airline walkround but perfect for GA and in-cockpit use. I just get the other guy to do the walkround
That said... the local bargain shop had some AAA battery 9LED ones for about £3. Probably more use in the flightdeck than the lenser which is better than most GA landing lights!
(this is all UK but I'm sure the same sorts of things are available elsewhere)