Friendly locals are usually able to get a sim card for you without any delay. I got my first one from a rickshaw driver (I actually bought his active sim card and phone) for a $10 more than it would have cost. A guesthouse owner did the same thing on another occasion. Make sure to ask nicely, because these people are on the hook if you do illegal things with those cards.

I once went through the official channels, too, and it was much easier than I thought. I didn't have a passport photo either, so I went across the street to get one taken. Then I came back the next day and picked up a working sim card. It's only a bother if you need the sim card right away.