I can't find the thread or the post, but I once came across a post on Touring about the neat stuff you can find in a discount or dollar store to use ion a bike tour. The list included lights. While I wasn't able to find dollar store bicycle lights, I did find some items I can use:
Insulated lunch bag
packets of instant oatmeal
zip ties and bungee cords
bicycle cable lock
True North tourer (www.truenorthcycles.com), 2004; Miyata 1000, 1985
Nylon stockings. I cut them into squares and sewed three edges to my panniers to make stretchy outside pockets.
A tiny proximity alarm. The alarm consists of two side-by-side pieces, one mounted to the window sash, the other to the casing. It is designed to sound when one piece moves more than a few millimetres from the other, as happens when the window slides open. (I was not able to make it work reliably on a bike).
Crazy Glue. For "instant" repairs. Always in plentiful supply at Dollar Stores!
I will help your search, but not all the way since my memory is shot. Unless typing this helps me remember.
I can't remember her user name... but she is a regular poster, a randonneur, lives in Canada at the moment as I recall and has posted a list of wondderful items found at the dollar store. Posts regularly in this section, and in the Long Distance Cycling section as well...
I know when I see her name I will think "no kidding"
In fact, I will think it right now.... Machka... No kidding!!!!! She listed several items in a posting...
I knew it would come to me right as I gave up!
Looks like the specific message I recalled mentioned specifically winter gear: