Cost of getting in-house certificate authority trusted

My company has an in-house certificate authority that is currently self-signed. Since we want to start using it for external SSL and secure email to our customers, we need to get it trusted.

Does anyone have a ballpark as to what it costs to get trusted root certificate for an in-house PKI? 4 figures? 5 figures? 6 figures? We employ between 2000-3000.

If I remember correctly, we were quoted something like 150k to start then 75k per year when we looked into this.