Unfortunately, it's not cheap. You're looking at $10+ per roll in development, and I'm guessing one roll of Ektachrome will be $10+ if it's anything like Provia/velvia. $20+ for one roll and that's without scanning which many have a lab do.
Don't get me wrong, I love slide film and I'm so excited to shoot this, but it's not exactly easy to make a habit out of shooting E6 for hobbyists.
You can pick up a decent 35mm kit for $100 off Craigslist, if you are careful.
Difference between $100 and say $15/roll total costs vs. $700 kit = 40 rolls @ 36 slides each = 1440 exposures until you start spending more than if you bought digital.
(thanks to poster below, I have corrected my very bad math errors)
Don't get me wrong, I love slide film and I'm so excited to shoot this, but it's not exactly easy to make a habit out of shooting E6 for hobbyists.