I've been using small bots like @hugewhale
"Send 0.700 SBD or 1 STEEM To hugewhale URL as Memo , Resteem to 10.500+ Followers , Min 30+ Account Upvotes , Hugewhale upvote."

so I've spent around 10 sbd and received over 30 comments in one promoted post from people I never knew before. within one post.