Similar to Mr Millar, I'm using a 'workshop' type compressor. It's noisy, but I paint in a seperate garage with noise cancelling earphones, so don't mind... Not sure what the neighbours think.....
Mine was £50 in B&Q 6 or 7 years ago
The C5 'brush from RCS is superb as well. Been using one for a few weeks and haven't looked at my Eclipse. Brilliant brush, and great value.