1. Ask around about the best carrier. Coverage and call quality vary widely between the six national carriers. The carriers will tell you that they're perfect, so ask neighbors, friends, and co-workers about who has the best coverage where you live, work and travel.
2. Pay attention to battery life. A dead phone is no phone at all, so look for a phone's "continuous talk time" rating. Assume you'll be able to go a day without charging for each hour of talk time.
3. Test the speaker. Usually, you'll be able to make local calls with a test phone at the wireless store. Make sure voices come through loud enough and clear enough.
4. Take a hands-off approach when driving. Several states now require you to use a hands-free kit in your car. For a car phone, look for speaker-independent voice commands so you don't have to touch the phone to dial. Try to find a phone with Bluetooth wireless capability for the widest selection of wireless headsets.
5. Keep an eye out for nickel-and-diming. Your base plan may not include instant messaging, picture messaging, e-mail access or calls in rural areas. If you're going to do any of those things, make sure it's included.
You ahave give nice tips but this tips are also useful to buy a phone:-
1.What Functions Do You Want, and What Functions Do You need
2.Do a Sound and Display Check
3.Check the Quality of the Ring Tones
4.See Which Accessories are Included with the Phone
5.Find Out How Long the Battery Will Last
6.Consider the Look and Feel of the Phone
7.Take a Careful Look at the Price
8. Find Out About After Sales Service
I'm not an expert but I do play the piano. Older pianos can have a very nice sound to them. Make sure there are no cracks in the body. You may want to have it professionally moved into your home unless you have a lot of help.