What chat service to use on product site?

I want to add a chat box to my product site to catch sales questions.

I've got three requirements:
  • It needs to be free (I don't have a lot of financial room at the moment).
  • I need to be able to steer customers towards sales questions and prevent support questions (that's what GH and CodeCanyon support are for).
I found Drift, Crips, and Freshchat.

Any others I should take a look at? has a free version, but not sure of the limitations.

Crisp > Drift
Intercom is great too, but too expensive.

PRO tip: most of these have startup pricing. Both Intercom & Crisp do, you just need to ask their support for it

Crisp is awesome, even on the free plan

I also use Checked all other services before.

drift or facebook messenger its free