SonicWall - Difference between a broker and a vendor/distributor?

I was working with a company looking to get some SonicWalls for our business.  After getting the quote, I ended up finding a well-mentioned site for SonicWall firewalls and they were around 40% less that very day.  I asked about it and the SonicWall vendor stated that the website I was referencing was a broker; but they would try to get the price down for me.

I do feel some guilt because the business really helped me out in figuring out what I needed, but a 40% price drop is too significant to ignore across our multiple locations.

What's the difference between me buying it at an online broker versus working with a business that SonicWall endorsed?