An update. I put in an order through alibaba for 4 of the 120ah cells that member kmcintyre used. This was my first experience with alibaba. I received only one response from China suppliers. The cost was $43 a piece plus $114 to get it here making a total around $280. Prices are up. Add in a BMS and cost for a DIY is approaching the sale price on the Renogy battery and the SOK that Will Prowse gave favorable reviews. Note, these are both 100ah batteries.
I considered the SOK because it can be disassembled and parts replaced.
I'm going ahead with a DIY mainly for the learning experience and I like to understand how things work.
Thanks all for the information and insights.
I think you'll like them. It'll take a while to get them.
The next thing will be getting the app installed and figuring out all the settings assuming you got the bluetooth BMS.
I'm not sure what prices you see for those other battery packs on sale but you should be around $325 for your 120ah cells and BMS which is about what I have spent on AGM batteries.
Have fun!
Kevin