yarn dilemma

ok, here's the dilemma i have in the world of yarn.

i like to make small projects. projects that don't take a lot of time. Hats, scarves, little stuffed animals. the problem that i have is that if i need a new color yarn for a small project, i have to go and buy a whole skein of it, usually 5-7 oz. and given the amount of projects I do, this yarn piles up. I have a 20 gallon plastic tote crammed full of yarn.

i guess this means i should get knitting, huh? but i really want to do these:

http://technabob.com/blog/2009/10/18/amigurumi-mario-playset/

and this would require me to get more shades of brown for the goomba. i'll dig through my stash. maybe i have something that will suffice.