Anything you like - the world's your oyster! Pick something you enjoy making, that doesn't cost too much and which you can sell at a profit. A browse round a local craft fair should give you ideas.
Some kids work with their parents acting as their financial manager, (someone over 18 is generally needed for make business transactions) and make stuff to sell on Etsy.com, I don't know how well those selling Duct Tape Wallets do, try searching there for different kind of products.
The seller cost there is 40 cents per item listed + 6% of any sales, you need to tack on a shipping charges as well.
You might look at Pandora style charm bracelets using glass or metal charms bought for as little as 10 to 20 cents each.
http://epandoracharms.com/
Clothing? Jewellery? Paintings?
you can sell absolutely anything online my cousin when he was fourteen was making bouncy balls outta rubber bands and making a fair profit. you could try the.
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I'm only 14 but I want to make some extra money. I cant get a job so I was thinking of making stuff and selling it but the question is what to make? any suggestions