Affordable Homes corridor: Any experiences with unexpected charges?

Visited a couple of projects in the Affordable Homes corridor last weekend. Brochures mein sab itna smooth dikhta hai, but site pe jaake hidden charges aur PLC ka game samajh aaya. Builder ne maintenance charges aur other 'misc.' costs bilkul mention nahi kiye the, yaar. My budget was tight and now this… Parents bol rahe hain soch samajh ke kar. Anyone else faced this bait-and-switch? Matlab, how do you handle these last-minute add-ons?