Keep you eye out for pricing. Sometimes the price is good enough that an oldie but goodie is a reasonable buy. A month or so ago I got some protected Panasonic 18650Bs for 4/$25. I thought that was a pretty good price and did them instead of trying for 4.35V charging cells. Got them from China in 2 weeks, free shipping. It seemed close enough for government work. They are going into a 3 pack TK75, which is my emergency light. If I am a bit judicious in the use of the light, that can be a whole lot of hours of light. Certainly enough for a night or three. I rather wished I had bought more. I just ordered 20 $3.00 single cell lights to sprinkle around the house.
Probably the next time I buy batteries for that TK75, it will be an 18650 format Mr Fusion.