St. Louis is 38% cheaper than St. Petersburg.
When comparing St. Louis, MO and St. Petersburg, FL, the overall cost of living indices are 66 and 106 respectively (national median = 100). Rent is $564/month cheaper in St. Louis, saving renters about $6,768/year.
Median household income is $17,839/year higher in St. Petersburg. Home values also differ significantly — the median in St. Louis is $185,100 compared to $331,500 in St. Petersburg.
Florida has no state income tax, giving St. Petersburg residents a significant tax advantage over Missouri's 4.95% rate.
St. Louis vs St. Petersburg — common questions
Other cost of living comparisons for St. Louis and St. Petersburg