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.
1 The cost to mail a first class letter is 46 cents for up to one ounce, and each additional ounce adds 20 cents. 2  Large envelopes (flats) that are rectangular and not too rigid or thick are 90 cents for up to one ounce (and 20 cents for each additional ounce).