Client: we want a website with so much functionally and interactivity.
Me: no problem
Client: what's the cost?
Me: xyz
Client:oh! I only need a basic website, with minimal interactivity

@4screendev or better yet, charge them what you normally would've charged for it. Any clients of mine who have tried to trick me into doing that have willing forked up the extra cash (and sometimes I end up charging more than what I was going to charge them originally)