A pair of good LiFeP04 100AH are only about $208 each, not much more than a lead battery.
The single is here: amazon.com/Timeusb-LiFePO4-Lifetime-Off-grid-Applications/dp/B0BBZL5BPR/
And the 2-pack is here: amazon.com/Pack-Timeusb-Lifetime-Off-grid-Application/dp/B0BLNR675J/
I now have three of them, two for the trolling motor and one for my Livescope system, and they are awesome. I couldn't justify the prices from a year or two ago, but TimeUSB is taking a big share of the market because of quality and price.