17.5k/yr for the lowest package was what I was quoted a couple weeks ago. It was actually not a terrible deal compared to most of the alternatives as far as value goes... but the starter package is way larger than you would need for most things. They essentially price segment the small startups out of the market. OTOH, many of the other GIS server licenses push 100k+, so that is why something like mapbox is getting people excited.

I'm doing a Foursquare/Yelp clone/mashup for my country with two friends, and we're using OSM + Mapbox because we figured it will be much cheaper than Google (and it's very easy and developer-friendly too).

We're still using the free version so we could have gone with Google, but we wanted to plan ahead.