Great advice from the guys above. We've used both the brands of spray paint that Supercheap carry;
i) "Powerplus" - 'Professional Touch-up paint' for $20 a can, and
ii) "Australian Export" - 'Paint' for $3.50 a can
We do prime, paint and clearcoat so you'll need at least 3 cans for a single colour rocket - based on the above, $60 bucks or $10.50 !
In our assessment;
i) The "Powerplus" is a more durable paint and can take a reasonable level of knocks.
ii) The "Australian Export" is still under review as the rocket we used it on we gave it rather a hardtime so showing some 'lived in' battle scars. I have since painted another rocket with this and it does seem prone to fingermarks still.
Here is a thread to the rocket and some pics using the "Australian Export" paint http://www.ausrocketry.com/forum/viewtopic.php?f=10&t=2142
We have recently gone to the local auto shop and found a mid range (price) paint between the above, this is;
i) "Motospray' - 'Quick Dry Enamel'. Firstly, not so 'quick dry'. Although I tend to let the rocket sit for days between coats giving them as much chance of curing as possible. I don't like the nozzle and the 'paint flow' when sprayed as much as the two above so this paint, so far, i'm not a fan of. To be fair, i'll fly it first and see how durable it ends up.
For the first time I tried the combined primer/filler and seemed to have good success, I haven't flown the rocket yet to determine how durable it will be though.
Hope it helps.