Just a few details to be cleaned up in this thread:
1. The 50-resistor Radio Shack assortment HD-5000 talked about consists of 1% tolerance metal film resistors.
2. As puppyslugg said, there is a fifth stripe on 1% resistors. The first
three stripes are the value code, the fourth is the multiplier, and the fifth is the tolerance band (brown, for 1%). This is simply a result of higher precision: you need more digits to describe that precision.
3. Because of the different numbers of significant digits, you can't compare stripe codes of 5% and 1% resistors. A 100K 5% resistor would be brn-blk-yel-gold, but the corresponding 1% would be brn-blk-blk-org-brn.
I second (third? fourth?) the recommendation to get a meter of some kind. Even if it's an ancient analog one you find used somewhere, get a meter. It's good for more than just sorting resistors. Even if this is the last amplifier you ever build, you can use it to test batteries.
Personally I only use stripe codes when examining resistors already in a circuit, since you often can't measure resistors accurately when they're in a circuit.
Using metal film's stripe codes is especially annoying, since the tolerance band (brown) is easily confused with a '1', so you end up spending a lot of time figuring out which end is which. With 5% resistors (usually carbon), it's less of an issue because if you see a gold band at one end, you know it's the tolerance band for a 5% resistor, because it couldn't be anything else.
I tried to learn the stripe code a few times, but I found the best way to learn the code is to just play with the resistors long enough. Eventually it just soaks in. Until you reach that point, using a meter's a lot easier, and it's more accurate besides.