Well kinda. The roots still have some dirt to keep them nourished while they're out of the ground, making them easier to replant. Just add dirt to the container it came in and place it in the window. According to my books and online research, it's only going to take about a week to have a new head of lettuce. Not only that, but, once planted, you can just continue to pluck the leaves from the existing plant, week after week, without further replanting. A dedicated lettuce plant, right there in your kitchen!
As a single head of lettuce, it's a bit pricey. But even if you just use this lettuce for sandwiches, you could save well over $120 yearly. That's just for starters, and it can be a nice chunk of change to put in the bank, or use for date nights.