Looking for a cheap apartment for rent in St Johns County, FL? With RENTCafé, finding an affordable apartment in St Johns County, FL has never been easier. We feature 2 low-priced rentals directly from property managers, with rents lower than the St Johns County, FL average. What is a cheap rent in St Johns County, FL? The average apartment rent in St Johns County is $1,151 per month so any rental south of $921 would be considered cheap here. Size matters though, so if you are in a market for a studio, expect to pay around $479 per month. If you’re looking to upgrade to a 1-bedroom apartment you’ll pay around $714, while a cheap 2-bedroom apartment will cost you about $863 per month.