Fuses and 4 guage power cable

Ok I am trying to find a 100 amp fuse and about 15 ft of 4 guage power cable and having problems.  I know I can find them on line but I want to pick it up today.  I have tried lowes, home depot and radio shack, Best buy and circuit city.  I have seen some 4 guage kits at around $60 but I don't need all the other stuff.  Can anyone recommend a source.  I was going to try a local shop but I'm not sure they would be to happy to sell me 15 ft of cable without them doing an install.

a local shop would be happy to sell you some power wire and a fuse if they wont i would say there a bad shop  also a 100 amp fuse is big for 4 gauge wire if worse comes to worse there is a 4 gauge wire kit at wal-mart with a 80 amp fuse for 30 bucks1974 ford pinto 4 15" punch Z power punch bd 1001 pioneer DEH-6700

Ok I went to a local shop and got the cable 4 guage($2 a foot ouch).  I have an 80 amp agu fuse that I am going to fuse behind the battery.  If I have an amp that has a 60 amp fuse and another that has a 20 amp fuse, will they be pulling a constant 80 amp?  And if so is my fuse going to blow at 80 or does it have to exceed 80?  Also do they make an 100 amp agu fuse?

Most amps run (at full power) a little less than the fuse current. So, if your amp came fused at 60A, it probably pulls about 55a when at max output. In addition, most amps don't blow "instantly". For example, a 60A fuse may be designed to withstand 70A current for 4-5 minutes before blowing. Regardless, I can't imagine that you are really pulling 90A consistently (which is a key, since most music consists of thumps/bumps/transients/etc) if your 60A fuse hasn't popped. If the amp came with a 60A fuse, you aren't going to be pulling 90A for any period of time without popping the fuse.