@SeaFury I make stuff and sell it and self-promo on Mastodon all the time. Folks are generally very cool about it. I keep trying to get other vendors I see at markets onto Mastodon - I get way more sales here than I do through fb/insta! (But also, self-promotion is a relatively small portion of my posts/engagements and I'm here as a Real Person, not as a Seller of Things.)
I get ick & block people who are ONLY selling stuff or who are doing any version of a pyramid scheme or dropshipping. But real people making cool stuff? Hell yeah I'm here for it, I want to see it and support it in whatever way is possible.
I tend to tag things with #shamelessSelfPromotion, location tags if I'm doing an in-person market, and then tags for what I specifically make. Yeah sometimes I boost a bunch of my stuff when I have an in-person market coming up, folks can mute it if it's annoying, it's only a day or two.