1990 Marathon Spirit ... Starter?

[RooWalk]

I have a 1990 EZGo Marathon Spirit (Serial 588692; Manuf. Code E1490).
It is my handy dandy farm vehicle. I have a spray tank in the back and a tool box in the front and the GoGO! takes me everywhere on the farm to fix, repair, examine ... and get the mail.
Last Winter (18/19), the gas cap (with the twisty frame) rusted and contaminated the gas. Spring (19), I was draining the tank and doing what maintenance I can when my place was caught in the floods OK had from the Arkansas River. I got about 8"-10" in the garage the GoGO! was sitting in.
I have been displaced since June '19 waiting for FEMA and mold remediation. Feb '20, I had an Aortic Dissection and spent 27 days in the hospital.
I am out, and back and things are starting to move with the house and barn.
The GoGO! is at a mechanic friend's place to be worked on. I still need a gas cap ... but the most pressing issue is it will not start - with a fresh battery and a new ignition. My mechanic friend is leaning towards the starter.
Where can I find the best deal on both the cap and starter??? My budget is rather slim between the flood and the heart surgery.
Thank you so much for the help!!!