The short answer
Apartment management software for a small owner has to do four things every month: show which units paid, chase the ones that did not, track repairs per building and report income and expenses per building or per LLC. Most platforms do this and charge per unit, per online payment or both, so a 60 unit owner pays $100 to $300 a month.
Letting does it at a flat price per size band, with no fee on your residents' rent payments and no onboarding fee. It does not collect rent, screen applicants or list vacancies: residents keep paying into your bank account by ACH, Zelle or check, and Letting reads the bank export to update every ledger.