Free preschool for a 4 year old?

Hi, does anyone know how things are here, I didn’t go to school in the USA so idk how it works in here, my son will be 4 in September 24th and I am SAHM with 2 kids, my husband is the only one working but we don’t apply for financial assistance, I was told that Kidango is an option but we have to pay 900 a month just for 3 hours, what about Tk is a 4 year old able to go to Tk and not pay, I saw on internet that Tk is free but I am not sure, I need guidance please