It's almost impossible to avoid fading with jeans - reason being, with traditionally made denim, the dye/wash does not penetrate deeply into the fibres, it just rides on top. With natural scuffing, sitting, washing, etc. the outer blue layer gets worn away to reveal the white underneath. This is the problem with ready made vintage - it looks fine at first, but since it hasn't been washed a zillion times (only sandblasted to look that way) the dye washes out and it doesn't look right. Doesn't matter if the jeans are cheap or expensive, if it wasn't washed (or treated so the dye doesn't bleed as much) it'll fade. To minimize fading, you can either go with dry cleaning (which introduces a whole other set of problems) or wash in cold water, with a gentle, liquid detergent. Something like Zero for dark colors works OK (won't totally prevent dark colors from bleeding, but it helps.) Don't use a washing machine, use a bucket. Dissolve the detergent in a little bit of water, then add some cold water, then the jeans. Dunk it/move around the jeans manually until you're satisfied they're clean enough, then rinse gently with more cold water (don't squeeze or wring out the jeans, just squeeze them gently.) At this point they jeans will probably still be sopping wet; I usually put them in the spin cycle of the washing machine to get the last of the water out, then lay them flat to dry. I don't like using the dryer since it shrinks everything (even on a low setting). Another thing which may sound gross, is to not wash your jeans too often. As you wear your jeans, the material will gently stretch and mold to your body.