Please can someone help me choose an air brush?

I need to buy one asap, but I'm a bit perplexed with the variety that's available! The prices seem to vary quite a lot, so I am of course wary of getting the best value machine - one that's reasonably priced but produces a good effect & is reliable. It's tempting to go for something cheap, but I'm worried it would be a waste of money! I won't use it a lot, so don't want to spend a lot on it though! Would also want to be able to adjust / vary the nozzel so that I can achieve a variety of spray styles / concentrations.

Do I need to buy a whole new set of colours to use for the air brush? At the moment I use Sugar flair paste colours, and it would be ideal if I can mix these with alcohol or something to make them liquid.......as buying a new set of colours could work out quite expensive again!

How do I apply a shimmer finish with an air brush? Do I dilute a shimmer dust with alcohol to use in the machine?

Please let me know what machines you do (and don't!) recommend!

Btw - I'm in the UK, so an air brush available in the UK would be needed!

Thank you, Katie