Most Instagram accounts treat comments as vanity. The accounts that generate revenue treat a comment as a raised hand. Someone typed a word under your post because they want something. The gap between that moment and your reply is where the lead is won or lost.
Start with the keyword. Use one word, easy to spell, and unusual enough that it does not appear in normal conversation. PRICE, GUIDE and LINK all work. Avoid words that appear in ordinary praise, because you will trigger on people who were only being polite.
Write the caption so the instruction is unmissable. State the offer, state the keyword, and state what will happen. Comment PRICE and I will send the full rate card to your DMs. People follow instructions when the outcome is specific.
The first automated message should deliver exactly what you promised and nothing else. Do not open with a sales pitch. Send the thing. Trust is built by keeping the promise the caption made, and the sale becomes possible only after that.
The second message is where qualification happens. Ask one question with a low answer cost. Are you looking for this for yourself or your team. Which city are you in. One question, easy to answer, and it tells you whether this person is worth a human conversation.
Route the answers. People who respond with buying signals should reach a human quickly. People who go quiet should get one follow-up, then stop. Chasing silent contacts damages your sender reputation and irritates people who were never going to buy.
Measure the right number. Not comments, not DMs sent, but conversations that reached a qualifying answer. That figure tells you whether your offer is working. If a thousand people comment and four answer your question, the problem is the offer, not the automation.