As an amateur economist, your SFist associate editor plugged in his own regrettable twitter handle. After a brief moment of calculation, the widget told me I'm worth roughly $131 based on my follower count, my 4,700 or so tweets and the fact that only 25% of the people following me are even paying attention. (To be fair, even I don't think many of those 4,700 tweets make much sense.)
For comparison's sake, Twitter apparently owes actor-turned-tech geek Ashton Kutcher nearly $2.2 million, because life is unfair and sometimes other people have more money than you. On the bright side, @SFist is apparently worth a cool $14,000, which should help pay for our coffee shop lunches and happy hour tabs for at least a few more months.
If you want to know just how valuable your own stream of sandwich tweets is, you can run the numbers right this way.