Vendor
Part of speech: noun
Definition: A person or a company that vends or sells.
Marketer
Part of speech: noun
Definition: One who designs and executes marketing campaigns.
Example sentence: There's so many people who have never heard of us, but I think what we've learned is you can't underestimate the power of a core fan base and people who believe what you're doing. I think they're the ultimate marketers. They're the ones promoting us.