I am cosplaying as a mad scientist, and was looking to buy a lab coat over the internet. However, the good ones appear to be stain proof...

How would I make it look like its been through hell and back again without breaking it? All of the costume ones seem to be $30 or more, and the doctor ones under $20, so I wanted to save some money by buying the doctor ones.

I need to know how make fake blood stains, fake colorful stains, etc... Any ideas?