Don't buy a new tire, man! You can have that fixed up in less time than it would take to put on a spare. All you need is a plug kit and a compressor to inflate the tire up again.
I just did one in my driveway the other day after work.
Your flat is the best kind to have because it is easy to find the puncture.
You don't plug holes in the sidewall like this. That's how you get blowouts on the highway. If it's in the middle of the tread, that's a different story, but this is not a good spot... Stay safe.