What is the potential of the business ?
Basically your cost is almost zero as the material is readily free from what you consume day to day, the only cost is the earring hook ( correct me if I am wrong ).
What is the price for a piece of earring like this ? To be honest, I have no clue at all, but I don't mind paying something like RM10.00 as a gift, it looks special to me and furthermore, it is handmade.
If let say you price it at RM8.00 per pcs and you manage to sell 10 per week via friends, office mate, relatives, Internet or even night/morning/flea market, your income will be around RM320.00 per month.
How can I start this Business ?
First of all, you need to find a local wholeseller who sell the earring hook ( http://www.cjshee.com/ contact : Mr. Edward Yong ). Visit the shop and you can ask for assistance on how to make an earring using their product.
Try to experience it by making some sample and wear it during your class, work place and weekend. Ask oppinion from your friends and officemate and try to improve it. Take order if they are interested.
My Opinion
This is an excellent idea, not only that it recycle, it is also very unique. I strongly suggest you may start this business with a group of close friend, not only it is fun, it can also create more awareness ( Imagine a group of you wearing this custom make accessories from recycle drink can ).
Internet is definately a good place to market this product, not forget to participate in your local flea market as well.
The best part is the start up cost is very very low, all you need is some earring hook, recycle can and a plier.
Please do caution about the sharp edge of the can and I am sure you do not want to injured yourself and your customer.