Fresh Basil

If you're doing a one-off meal, you can buy 'fresh' basil from your local supermarket, once picked/cut it won't last long as it soon loses it's freshness.

You can buy the plants but why not just buy a packet of seeds, grow your own and next time you want basil it will be totally fresh and pretty cheap. Also it looks nice on your windowsill in the kitchen and has a lovely aroma, as well as deterring flies.