Lightroom CC is Adobe's new plan for delivering Lightroom with frequent updates that includes new features. The CC plan includes the Lightroom as well as the latest Photoshop, and the cost is $10/month. There is also Lightroom 6, which started out with the same features as Lightroom CC except for Lightroom Mobile. Since Lightroom 6 was released there have been new features added to Lightroom CC that those who purchase the standalone upgrade will have to wait for Lightroom 7. If you want to purchase the standalone version, here is the link:
Lightroom is near the bottom of the page. Click on the Buy Button, then indicate what version you are upgrading from. The price will then change to the upgrade price. Just follow the prompts to complete your purchase.