What kind of workplace will you be using this light in? I have a USB power bank and a pair of these USB lights:
https://www.fasttech.com/products/1604606
I'll use them as a directional work light when I'm doing normal work around the house in areas that need additional light. It's not very rugged though, so I wouldn't use it in a shop-type environment.
If you are in the US, these Harbor Freight mini work lights are cheap and popular:
http://www.harborfreight.com/27-led-portable-worklight-flashlight-67227.html
...or build up something like this:
https://budgetlightforum.com/t/-/3057
I've been toying with the idea of setting up a 12V SLA cell in a box, and building up an enclosure with several of those cheap 12V LED bulbs to make a cheap portable version of this (Unfortunately, I can't see the pics, not sure if they've been moved or if they are blocked by my work network):
https://budgetlightforum.com/t/-/21483