I think it's a good idea in principle. I had (since 6 months ago) a little business selling handmade children's gifts so did a lot of craft fairs. There was a regular at one who sold wool and she did well- crafters are very likely to come to craft fairs! However, your outgoings are high- especially your start up costs- you would have to "take the plunge" and buy stock. Also, some craft fairs are, well, just that-to sell crafts rather than craft supplies(although there are specialist craft supply fairs). Whereabouts (roughly) are you? I paid, on average £40 for a 6x3ft stall for a Saturday or Sunday in and around Leeds. Plus around £50 per year insurance. You can only really work 2 days a week. There's enormous competition on line. The lady who sold at my regular fair sold Llama wool and had a whole themed stall- wool, hats, gloves, kits, even llama hand puppets, badges and pens etc. She found a niche. I think her stall was an extension of a physical shop though. To be really honest I don't know of anyone who makes "good" money doing this sort of thing(I didn't). It's a labour of love and there are a lot of retired people or women with young children who do it out of convenience for "extra" money.