Dont buy just the spoke wrench, consider buying a truing stand as well.
I learned how to true when I ordered a bike online and the wheel was so out that it wouldnt spin. Took me 2.5 hours to get it but I learned. Now i can true a wheel in about 10 minutes, depending on the wheel. It is a valuable skill. I have trued and respoked wheels about 30 times since for work and personal bikes. Even if each true was $10, I have saved $300+