I have an iPhone and don't know about Anki on Android but this Android Anki app is free and can create & edit decks. It looks like if you want to import a deck you created on your desktop computer, you have to put it on an SD card. (A lot of printers have SD card writers.)

Since the iPhone app is what I use, I'll talk a bit about it. You can create and edit decks on the iPhone app but I only do this if I'm adding one or two cards. (I don't know if you can do images and audio from there.) Mostly I add stuff in the (Linux) desktop app. To sync stuff between the desktop computer and the phone you need a (free) ankiweb.net account. If you want to sync images (including LaTeX) or audio, you'll need a Dropbox account (free for the amount of data you're likely to need to store).

The desktop app can import stuff in tab-separated values format (or comma-separated or a few others). Most of my cards were generated by little one-off computer programs that spat out TSV.

You can also add and edit decks from within the ankiweb.net interface.

Here are some things I use Anki for:

• Arithmetic and other math stuff.
• Birthdays of family and friends.
• Computer stuff (e.g., library function arguments).
• Things I often forget, like checking that I have my keys before I lock the house or car. (Example question and answer: "When's the last time you got out of a car? Did you check what you should have?" / "Dome light, keys, headlights, lock.")
• Song lyrics. (I'm a musician.)
• Roads in my area (e.g., "Haggerty Rd is about a mile east of ...").
• Months: how many days in each one, and what is each one's ordinal number. (Like the multiplication table, this is something that I didn't master when I was a kid.)
• Rules for card games and board games.
• Holiday dates. (E.g.: "When is Mother's Day?" / "Mother's Day is on the second Sunday of May.")

If you haven't already, you'll want to read what Gwern has written about spaced repetition.

Edit: Let me add a warning about something that has bitten me a few times. If you access your decks from multiple devices, or from one device and ankiweb.net, follow this advice about syncing (and, to be safe, avoid having a deck open in two places at once).

I haven't used the Android app, but making customs sets is all I do with the iPhone version. You can embed images & audio files very easily and sync everything through Dropbox. You can edit the layout of cards in HTML or even in LaTeX. I am cheap & I was wary of spending the money to buy the app, but I would say it has been one of the best investments I've made in my life.