All I can say is we apparently have different ideas of what a "beater" car is. I hope you're right though and that EV batteries have a 15-20 year usable life.
I see first-gen nissan leafs going for $3k, and I see tesla 3's for $16k
30kwh of tesla powerwalls is at least $23K. Sadly, those used cars don’t support v2h or v2g.