Simple green(as posted), spray nine, white vinegar or ammonia works great to clean out dried paint
I think one of the the best banf for your your buck airbrushes is the DeVibliss DAGR. They have the quality of an Iwata Kustom(around $300) but the DAGR sells for around $120 to $130. I own the Iwata HP-CS and may get the DAGR in the near future. The best thing I have seen for your airbrush is a inline or at brush pressure regulator. Iwata has a nice one with filter that you can get for around $15-$20 or so
For paint I use Golden, Liguitex, Delta and few others. I have about 60-70 bottles of Createx that I dont use. With the Auto-Air you are suppose to thin/reduce w/ 4011 Flash Reducer this aids in thinning and drying. Using the 4011 and use heat to cure gives far better results then thinning w/water. Acrylic paint has to be heated to fully cure