¿What is the best economic model in order to use Intercom?

If you are a rather new company you can be eligible for Early Stage offer. https://www.intercom.com/early-stage You should not be older than 2yrs and should not have received more than $1mil investment. You get all Intercom services (Pro level) for just $49/month up to 500 people you serve (active people are those who you had contact with in the last 90days). You get up to 3 inbox seats (your profiles that can communicate with your users). The offer is valid for 1 year. After that, I had Intercom clients that did not grow that much so they got this offer extended to $99/month for up to 4000 users they serve (I believe, not entirely sure). It can be quite expensive, depends so much on the number of active users you are serving through Intercom, and the number of features that you use (i.e. stupid thing is that you might use Custom Bot just for a small segment of your users but you still pay per active user of the whole product). I've had Intercom clients that were using almost everything and were paying about $10k/month (with a huge number of active users).

Plus is $39/seat (User) per month. Its enough to get started