Ask HN: How to deal with hagglers w/ future opportunities?

I've noticed almost every potential client, when they are considering buying our product or paying for some services, they always say things like, "This is our entry point." or "I see lots of potential later." "I know lots of people in this industry." They are trying to build excitement, but I've learned these claims almost never pan out.

Have you noticed this in your business? Is this something all customers do -- like a negotiating strategy? Is it a warning sign that I should walk away? Any suggestions on how to deal with this type of haggling?