For DIY, you can go to any parts dealer (Autozone for me).
For getting it done, don't go to a franchise (Sears, etc.) goto an independent shop. They are usually operated by a mechanic who has superior knowledge and decided to strike it out on their own.
Good Luck.
P.S. Try it yourself. It is a simple fix you can try and learn about cars.
A question first: how do you know you have one bad plug/wire? Is there a miss in the engine or did one break? It's false economy to replace only ONE plug or wire....just do them all and do it right.
About the cost: I just bought a 4 wire set for my Suzuki Sidekick......$29.99 at AutoZone....and Wal-Mart will likely have the plugs you need at (I'm guessing) $3.00 each.
Be sure you have the tools to do this before you start the job....and ask your close friends (or Yahoo Answers) for tips.
Do them all at once, don't replace just one of them. You can just buy the wires and the spark plugs yourself, try and a parts store or you can look at www.sparkplugs.com they have good deals on plugs and wires. Once you get them you can either install them yourself or you just go and take it a local car repair shop and ask them if they will charge you a small amount of labor to put them in.
