Automatic is an interesting hardware-software combo that makes information from your vehicle accessible on your phone via an SDK and a series of apps. It's an interesting idea (even if the nondescript name makes it nearly impossible to Google for), and thanks to a standard OBD-Bluetooth setup and a relatively decentralized structure, it doesn't require any subscription fees. You do have to buy the adaptor, of course, and it's relatively pricey at $99.95. But right now you can grab a 20% discount.
Head over to the Automatic online store, which for the moment is only shipping to the US. Enter the code ATP2014 before you check out to take twenty bones off the price. That's about it. Automatic accepts payment from standard debit or debit cards, PayPal, or even Bitcoin. Standard shipping is free, and you can return the Automatic OBD within 45 days if you're not satisfied. The adaptor works with both Android and iOS, and it's compatible with the majority of cars sold in the last 20 years or so.
Automatic's partner apps include Expensify, Nest, Pebble, IFTTT, and Jawbone Up, among many others. For more info check out Bertel King's review of the app and service from last year and the coverage of the new Automatic app store.