cheapest will never be best……………..
…………….and the best will never be cheapest.
these seem mutually exclusive.
the cheapest might be rural mississippi or someplace similar, and you can get real cheap by living in a tin shack.
the best might be urban san francisco, new york, portland, or smaller cities like austin, boulder, etc.
for a californian, it might all be accessible.
for others, i might suggest a college town attached to a state capitol. the suggestions for austin may make sense; so might madison(WI) davis(CA) corvallis(OR) hartford(conn) etc etc etc. you’ll get some diversity, educated folks, cheap food, potential investments in student rentals, access to countryside, the opportunity for community – a possible escape from suburbia without being in the boonies…