I only make cakes as a hobby and buy different colored fondant for cakes. Most of the time i do not use it all and it goes to waste. My ?? is would it be worth it for me to buy an airbrush and cover cakes in white and then spray it? If this will work would the cheap Duff airbrush work?
I'll start off by saying I'm VERY biased when it comes to recommending airbrush equipment.
I am NOT a fan of the cute, tiny "starter" class of equipment. Sure, they're OK of small stencil work and shading.... but that's it. Equipment in this class can be very hit or miss when it comes to quality, not every line offers replacement parts (which is a MUST when owning an airbrush) and the air pressure is very low.
If all you're going to do is basic small stencil, sure, why not. Just know that the equipment won't be practical for airbrushing a color change to an entire cake. Caaaaaan it be done? Sure. Just like I can paint a house with a paint brush.
For the best value and bang for the buck, take your 50% off one item from the craft store and buy a Badger set. I don't use Badger, but they are a solid company and cary replacement parts.