I knew a guy who spent all day chewing elastic bands.
2 years later he was selling chewed elastic bands and making 3 billion per second.
True story.
Or how about this for an idea, you make a good quality elastic figure called 'Elasto Man' with a simple wood core, and take to craft/trade shows, get a few orders and make a few quid - refine the product based on feedback. Then pay an SEO company to market custom elastic made to order and measure products with no size limit with your sample best seller as the figurehead and cool string type bent over logo
If it goes viral, expect your first million, but only if it goes viral e.g. offering it to Dragon's Den for % share or riding the free advertising, otherwise expect 3-25k from corporates/hobbists annually if you can bolt on colourful printed backgrounds and metal stands/bases as additional extras with appealing messages such 'In life, you can succeed, just be elastic!', and then invest (with a business loan from the bank) in an app called 'Elasto' marketed by Elasto Design Bureau (your company name) to design your own figure in the form of a simple string game (stretch and drop in to place with the fingers to make it playful), with user rankings for the best designs and best rated which you can strangely order along with free competitions to win a limited edition 'RED', then yes, in 2 years you could probably make something of it (if you excuse the pun). All you need is elastic bands
The potential billion.. get an independent developer to make a free to play elastic online multiplayer game called 'Elastro - the coming war', followed by 'Generations' for kids using an existing engine to design your own world with elastic bands to build bridges etc. and purchasable upgrades such as elastic army officer/general to protect your elastic creations from destruction by the other players trying to take you over, and the ability to purchase an elastic jail to generate income from the government with further purchasable upgrades to make the prison bars stronger instead of the usual off the shelf elastic (to stop your prisoner from escaping by stretching the bars), though the other side can purchase the platium item in the game - 10 second scissors, then you may have 'chance' at your first billion, worked for lego/minecraft
Then you can be as wealthy as the Royals - Angilion, take note.
I know, I am a genius - I am going to copyright it, and sell the rights