Full colour is when your whole hair is coloured with ONE colour, (bleach or dye) to the roots.<br />
Foils is when you have sections of your hair coloured and you can have more than one colour in this way. I have a couple of different blondes in mine. You can have the whole head, half head or top section done depending on the look you're going for. I have whole / top / half / top / whole / top - in that order about every 2 or 3 months to keep my colour. It's cheaper than having the whole head done every time and much, much, much better for your hair. <br />
Love messing about with my hair.
I can only guess that full color means you're coloring every hair on your head one single color, and half-head foils means highlights.
I like dye in streaks my hair.
Full colour is when you couloir your hair in one colour and half head foils I when you put a different colour in your hair, similar to streaks