Regular Coke and Coke Zero both have the same taste. In fact, Coca Cola has a series of Coke Zero advertisements for Coke Zero that depict Coke managers consulting lawyers to see if they can sue Coke Zero for "taste infringement".
Comparison chart
Price
Prices for soda vary depending upon the retailer. Here are the current prices on Amazon.com:
Comments: Coca-Cola Zero vs Coke