$6.99 for USA and the app, v.s. $36.99 for the USA board game.
$0.99 for 1910, v.s. 19.99 for the board game.
$5.99 for Europe and 1912, v.s. $69.15 for the total board game
$9.98 for Switzerland and India, v.s. $29.99 for the total map collection
$4.99 for Nordic, v.s. 49.99 for the board game.
$4.99 for Legendary Asia v.s. $34.82 for the board game (Note: with the board game you get Team Asia)
The app is essentially the board game on your electronic device.
It offers a tutorial (though it's about as forceful as a corrupt elementary school teacher), as well as the ability to play left-handed, change your color and avatar, adjust the sounds, and adjust the size of the screen. Some people don't know this, and so play the big, ugly format on iPad, or the tiny, hard to press format on the iPhone. Idiots.
You can play against real people online, on the same Wi-Fi, using the same device, or against bots. The online mode also has ELO ranking. Unfortunately, ELO is not appropriate for TTR, so you'll find the online community can be a bit, er, evil in terms of playing.
You can also sign in with your DOW account.
You may notice that Ticket to Ride has a rather low score on the app store. This is because of the migration. A while back, DOW decided that it would be beneficial for everyone to make one app, instead of having to update 3. So, Ticket to Ride Pocket and Pocket Europe were removed from the app store, following a re-write of the iPad app to allow all devices. People with Pocket were then told to buy the normal app at a decreased price of 2.99. People freaked. Crying about how they shouldn't have to pay for access to new maps, asynch and more. Idiots.
Then DOW threw in the new Pennsylvania map for the migration. I'd like to point out here that the Pocket users had a SERIOUS F***ING BARGAIN. But when people didn't follow the instructions, they didn't get Pennsylvania, and lost 1910, Europe, and Switzerland. They freaked (again). Then people who owned the normal app before also started crying because they were promised Pennsylvania. They can't read and you should hold no respect for them. Finally, people complained about the UI, which some (me included) people think is beautiful and well-explained, while the rest struggle to open a game. Idiots.