I recommend buying original charger. I bought some cheap ones from eBay and they lasted only like a month. They even sent me a replacement charger after one broke, and the replacement broke too. Amazon sells original iPhone chargers for a very low price.
i bought Univeral Charger for iPod, iPhone and Touch at awholesalecompany last month. The sleek Design and compact Size is perfect for Travel or Home.Intelligent clip inside to product from over Charging & over Heating