In an interview with AutoBild, chief designer Franz von Holzhausen says Tesla will "probably" reveal its more affordable car at the 2015 Detroit auto show. 

That car is said to be named the Model E. 

Today, Tesla sells a Model S, which has a base price of ~$60,000. It has the Model X, which is more of a SUV, set to roll out next year. The X will probably cost as much as the S, if not a little more.