Mastodon is not a marketplace, where you set up your little booth and wait for the crowd to walk by and check out your stuff.
This place is a lunchroom, or maybe a campfire; it's up to you to go and sit next to people and strike up a conversation if you want interaction.
Sure, you can sell stuff here, I've bought plenty of things myself that I saw advertised here. But it's not a storefront in a mall, it's door-to-door sales; you need to build a little trust first. Because we're not here to browse or shop, we're here to sit by the campfire.