Definitely do this stuff on your own. It's not difficult, gives you a sense of satisfaction that it was done right, and empowers you.
Also, consider buying one of these:
BlackJack Tire Repair | The Leading Manufacturer and Worldwide Distributor of Tire Repair Products
They're awesome and you can repair a puncture in under 5 min. The plugs vulcanize themselves to the tires. I tracked my car at Road America with three of these plugs in the rear tires. No problems.