On eBay or forums, you will see listings: "NFS Heat Offline Steam Account – $2.00." This is the closest you will get to a "free" experience (though it costs a few dollars). The seller gives you a login, you set Steam to "Offline Mode," and you play until Steam requires a re-login.
Instead of buying the game outright, you can subscribe to EA Play or Xbox Game Pass for PC. Both services include Need for Speed Heat in their standard libraries. Need For Speed Heat- Free Steam Account
The only downside is that only one person can play from your library at any given time. However, it's a fantastic feature that Valve explicitly supports, unlike account sharing. On eBay or forums, you will see listings: