The premium membership for car-traxx.com is free for the first 30-days. After the trial membership expires you can renew by logging into Car-traxx.com. Click on My Account and then click on premium.
Car Maintenance intially comes with a 15 day trial license. After the license expires you must purchase the app from the Mac App Store to continue to use the product. Click the Mac App Store link below to purchase.
You can download the app from iTunes. Just click on the link below.