Remember, when you're using a "free" service, you're the product, not the customer, so don't complain when the company sells its product(users, or at least their eyes and ears) to its customers.
It's not exactly hard to find deals and discounts for Spotify Premium either. Six months free, $99 for the first year, etc. I think they also offer a student rate of $4.99 per month or something.
I love Spotify. Even the full $10 per month is worth it to get the full spectrum of music and avoid any annoying ads.