I have two gravity fed AB in fact I have this: http://www.ebay.co.uk/itm/New-Gravity-Feed-Airbrush-Dual-Action-Compressor-Kit-Nail-Body-Art-Spray-Tattoo-/400356877974?pt=UK_Crafts_DrawingSupplies_EH&hash=item5d37212696 it is okay for a starter set as it is low noise, small, portable, however it is just for starters, a tank version is a must once you get proficient with it. I have a cheapo AB and it is okay, however the button sticks like mad despite cleaning regular. My other is a Hansa Hobbyline at around £90 and that is rather good.Getting the cheapest is not always the sane way to go even if you are unsure of AB and a newbie. For the extra few quid the experience can be better than using a really a cheap option and struggle with it and put you off. Get the best you can afford without blowing big bucks.
Si