Download offer up from the apple store or play store and search that up there’s many good deals and sometimes comes with games and controls included for cheap!
First of all you can't find a ps4 for free unless you get it off a close friend!
Offer up is good for cheap prices! Walmart or any stores don't sell cheap prices! Your only luck is winning one or getting it off some websites or apps! Make sure you don't get scammed tho!