In using a guitar amp, it's important to know how to manipulate the amplifier to achieve a number of different effects, including a clean or dirty sound. Learn about using the bass and treble knobs on an amp with help from a professional guitarist in this free video on guitar amps.
A 10 X 13 envelope (must be less than 1/4 inch thick) is considered a flat and costs 80 cents for the first ounce and 17 cents for each fractional ounce after that up to 13 ounces.
It will depend on the size of the envelope and the total weight. A #10 envelope is 4-1/8 x 9-1/2. It is the most common business envelope size and is commonly used for standard 8-1/2 x 11 sheets of paper. Seven pages of copier paper plus a #10 envelope is within the 3.5oz limit for 1st class mail, but it will cost 59 cents to mail it. Better to check with the USPS or add another stamp than to take the chance of having your envelope returned for insufficient postage.