Quick answer. The questions that reveal the real cost and fit of an RCS vendor are about the things providers tend not to volunteer. Ask: Is your quote all-in, and will the invoice match it? Are carrier fees and taxes passed through at cost and itemized? Are there setup, activation, or per-RCS-sender fees? Is the inbox, are bots, analytics, and SMS/MMS fallback included or extra? Do you charge more for the API than the app, or gate features by tier? Who handles US carrier and sender approval, and how long does it take? What are your support hours and SLAs?
These questions surface the gaps between a low headline rate and the true bill. A vendor that answers them cleanly — all-in pricing, pass-through fees itemized, everything included, no API/app price gap, hands-on approval — is offering exactly the transparency that's hardest to find in this market.