For general use, I've never had an issue using an "OTC" clay (e.g. mothers). As far as lube, I am a fan of using soapy water. It works great and cost next to nothing.
many/most will use a rinseless/waterless wash and dilute it to QD/clay lube specs which will save you money since there are other uses as well. here's some good info on clay and alternatives...