Americana makes an acylic paint that is perfect for this application. It sells for .99 for a 2oz squeeze bottle and comes in a myriad of colors. It is a little thicker and covers well. More importantly if you paint it on straight from the bottle, it will seal your papermache product. They dry flat and relatively fast. No problem with washes or drybrushing.
Available at Walmart, Crafts & Stuff, Hancocks or Michaels.
There are other companies that carry a similar product of paint. This is the one I've been using and have the easiext acess to with the best results.
Mike
"Imagination is the dye that colors our lives"
Marcus Aurellius
A good friend will come and bail you out of jail...but, a true friend will be sitting next to you saying, "Damn...that was fun!"