Some non-studded winter tires come with the option to have studs added. Snow tires like the Arctic Claw Winter WXI are great (and affordable!) winter tires that come ready to be studded. The best snow tires for a Subaru Forester, in general, the Bridgestone Blizzak winter tires—and they’re so good, you may not even need studs.
Just like you shouldn’t leave your winter tires on in the summer, you shouldn’t keep your studded tires on unless you’re driving on icy roads. Driving with studded tires can damage the pavement and lead to deteriorated roads. Some states even forbid using studded tires in certain areas, so make sure you’re clear before heading to a new place with yours!