[meaty]

Actually the only answer to feature creep regardless of project size is "we'll get back to you with a new quote". Simply because you dont know how much effort is involved on the spot.

People who buy things from you know how to screw things out of you as a rule and this is a well known tactic usually disguised as ignorance.

[joshcrews]

I've been handling offering flexibility in fixed big projects by sharing my Pivotal Tracker story board w/ feature estimates and letting them choose which features to axe to get their new priority scheduled.

In addition I've also been offering a fixed amount of "freebie points" for 'not yet discovered features'. That helps define that yeah, I'm going to do a couple extra things not defined in the scope, but it's fixed amount and when you've used them up, there's none left.