Reseller program?

Thank you for reading. I'm confused over the reseller program. Let's say that a domain is available but my client is unaware that it is available.. would the domain show on my website as a higher amount than it shows on GD? Here's a scenario:

 

Client: I want a LLLL.com

Me: "yesok.com"

Client: How much?

Me: $$$

Client: I just went onto GD and it's selling for much less, so I prefer buying through them instead of you.

 

If the above mention scenario is true, how is GD and resellers helping each other sell domains?