Shoot for that price you could get 2 and run them in parallel lol.
NEVER NEVER EVER DO THAT! (run any batteries in parallel) by choice on a boat, or elsewhere if you can help it. The reason is that as they age, one will discharge faster than the other, and that one will drag the other one down with it. If one has a bad cell, the other one will discharge itself trying to (unsuccessfully) charge the other. It does that as they are just sitting there, connected to each other, not just when you are running the trolling motor. Yes, the BMS in Lithium batteries will control this somewhat, but it's still not as ideal as a series battery setup.
Regardless of battery chemistry used, for trolling motor applications, it is far better to run a higher voltage motor so that you have properly sized batteries in series. Example, a particular power output (pounds of thrust) for a 12V battery/trolling motor might run at 50A load. You can get that same power output in a 24V system running a ~25A load. Guess which discharges batteries faster?
If I were going to run two 36V Lithium battery banks (because one might not last long enough), I would run off one until it reaches discharge, then switch to the other. That could be done with a mini-cutoff battery switch, or a setup with a manually switchable breaker on the wiring to each 36V battery. The breaker outputs would be wired together, and you'd turn only one on at any given time to get the desired battery isolation.