I've spent the last 15 years fly-fishing and agree with Ian,
the only free flies I've had have been from the mags.
Once found 12 of which 8 were in v. good condition from a very steep grassy bank at Gyhll Head trout water.
What sort of [u]free Trout flys [/u]are you looking for, I know of a few sources like above on the Salmon and Trout mag and FlyFishing and Fly Tying mag.
But did you know there is nothing better than [i]making your own [/i]and then catching fish on them knowing that you aint paid a fortune for them.
An average lure costs about 3p to make and a Pheasant tail even less than that Drys are about 2p once you build up the materials.
A good basic Kit containing just about everything you needvice tools feathers materials ect costs about 30.00 from Pegasus in Yarm.
i have managed to get some free flies form carlsons they sent me 1 flexi buzzer 1 blushing buzzer 1 epoxy buzzer & 1 pearly invicta  so if amyone wants some free flies then you just need to send an e-mail to them with your name and address there e-mail address is firstname.lastname@example.org. and threre website address is www.carlsons.co.uk .