"Preventative care" refers to the field of medicine called preventative medicine/care/health, which specifically aims at making regular checkups and other monitoring facilities free and accessible in order to improve health via early-detection.

Oftentimes, doing these sorts of things lowers your insurance premiums or makes costs lower if something does happen (not always, but sometimes). These sorts of things are also generally free as it costs the insurance company less in the long run if you're doing them frequently enough.

Perhaps a bit of a misnomer, but "preventative care" doesn't necessarily mean medicinal prevention of any sort.