- The power of an amp can be determined by the wattage of the amp. For playing at home, an amp that has anywhere from 1-10 watts (called a micro amp) will do the job, but keep in mind that although these are the lightest weight amps you can find, they're not ideal for more than personal practicing. These units just don't have enough volume when other people are playing, and if you try to play a gig with one of these, you're probably going to be the butt of more than a few jokes. Consider it fair warning.
- For rehearsing with a band, something between 10 and 30 watts is ideal. Make sure your amp has at least a 10-inch speaker.
- Crate combo amps, either 1x12" or 2x12", with at least 50 watts of power will do the trick for playing live. Granted, you're not going to rock out in Madison Square Garden with something this size, but this is as small as you can go and still have an amp that will serve you well on the club scene.
- The amps listed above are all combo amps, meaning they have a speaker and the electronic board in one unit. There are separate head and cabinet amps (heads and cabs) that have the speaker and the board in different units. Even the cheap heads and cabs are not that cheap, and really, unless you have an arena tour planned, you don't need one. And if you do have an arena tour planned, why are you buying your own amps? Get the manufacturers to give you one in a sponsorship deal!
Source : By Heather McDonald - http://guitar.lovetoknow.com/Cheap_Guitar_Amps
