Perfect if you live in a very sunny area, the cellphone strap from Japan’s Strapya is a miniaturized solar cell that can charge your cellphone. Excellent for the cellphone-glued teenie boppers that just need to inform everyone on who is dating who.
The solar cell only has a lifespan of about 500 charges before you need to buy a new one. Unfortunately, the product page is written in Japanese. I can’t read Japanese, but it appears to cost 1,900 Yen or about $18 USD.