I myself have considered tying custom flies, but also as supplemental income in retirement. I believe as has been said, you have to have some patterns not commercially available. I still purchase a few, but tie almost all my nymphs. I have come up with a streamer that is pretty awesome. I too don't believe you could live on the income from just tying. I have tried many commercial ties, some were decent, most only survived a couple takes. Filling boxes with cheapos is a waste of money just to say you have them. Commercial materials often vary in both color and texture, and you are never sure of hook quality. I have found a couple of hooks, that are dirt cheap and very strong and sharp for little more that pennies each, and most common sizes are available.