I WAS WONDERING IF YOU COULD HELP ME.  I NEED TO DYE AN ACRYLIC ROBE FOR MY SON'S HALLOWEEN COSTUME.  IS THERE ANYTHING THAT WILL DYE 100% ACRYLIC?  I'M TRING TO DYE IT A MEDIUM TO DARK BROWN.  ANY TIPS WOULD BE GREATLY APPRECIATED. THANKS. 

No, don't do it. Acrylic is much like polyester, when you are dyeing at home. None of the easy-to-use types of dyes will have any effect on the color of acrylic. See the information on "Disperse Dye" - it's a lot of trouble, and it is not a project that is suitable for a novice. Another class of dyes that works on acrylics is called basic dyes, but I consider them to be too unsafe for home use.

Next time you want to dye something, make sure that it is cotton, silk, or wool.

Instead, what you could do is *paint* the costume. Good fabric paints alter the feel of fabric only slightly (you can buy several different types at Dharma Trading Company), while diluted artists' acrylics will make it stiff and scratchy, but will cost less.