I think this statement is extremely poignant, "Because you're looking for a sense of security when you're spending your budget on a web app". I think a big problem is lack of knowledge on the part of the client. Most people just have no idea what it takes to build web apps. $1000 (or even $5000) just doesn't go very far. But without learning and experience on the customer's side, how are they able to bound the project to understand the potential costs?