How should I insulate my crawl space (California)?

Just moved into this house, the coldest part of winter may get down to freezing and the hottest part of summer will be around 105 for a week or two. Right now I can feel the cold through the floors. Crawlspace encapsulation sounds nice but also very expensive. Appreciate any advice!

Just moved into this house, the coldest part of winter may get down to freezing and the hottest part of summer will be around 105 for a week or two. Right now I can feel the cold through the floors. Crawlspace encapsulation sounds nice but also very expensive. Appreciate any advice!