Let me show you my little set up for dying at home. I use Procion MX dyes. They are cold water dyes that use salt and soda ash in the process. I got them locally here in Vancouver, BC, at Maiwa on Granville Island. I'm pretty much following Malka Dubrawsky's instructions from her book and workshop. Check out her great book "Color Your Cloth: A Quilter's Guide to Dyeing and Patterning Fabric" for her complete instructions and great project ideas.
First there's the waxing. I had started outside on the colonnade, then I moved into the kitchen under the stairs beside the hot water tank to be closer to the sink and less cold. I use Kona PFD (prepared for dyeing) fabric.
Next I waxed what I wanted to keep grey, then discharged most of the grey out of the rest of the fabric so that the red dye that I did next would be bright. If I hadn't discharged, the red over the grey would have created a very dark maroonish colour and I wanted bright red.
So the process is pretty much Wax, Dye, Discharge, Repeat, then Boil out the wax. The discharge is an optional step, but without it, you'll have to always dye from light to dark and the second colour will usually be a mix of your first and second colours. For example red after yellow will be orange, blue after yellow will be green.
The fabric that I used three colours on usually didn't turn out that great. They end up dark and muddy. Two colours and one discharge give you great results and that limitation actually makes me more creative and gets me thinking about what will work out and look great.