Murata (Sony) 18650 INR19/66 cells for 1 euro/piece!
Here's a way to get high quality Murata brand 18650 cells for about 1 euro a piece. The catch is that you have to disassemble a professional grade battery pack rated 52v/5.2amps. Thats 14S-2P in packing, so be careful and use common sense when working with them.
The batteries charge to 2650mAh so they are very good value for the price.
I bought mine from surplus from a dealer in Sweden on Tradera:
https://bit.ly/3jWmHC5
Battery charger, the best there is (I think): Dragon VP4: https://ebay.to/3k2f9Oc
Music from Epidemic Sounds, faults by me and be careful when working with 18650's!