HN:fixed or really low price voice api provider

[aspired]

I am looking for a cheap voice & messaging API for a startup gig. But seeing pricing of Twilio & Tropo, price that I will have to pass on to customer is way too high for startup to take off. Is there any fixed or really low price voice api provider?

[tron_carter]

I'm trying to understand...is it the scale you plan to be at makes Twilio/Tropo not affordable? Because if SMS/Voice is really core to what you're doing, you can roll your own infrastructure. Or go with Twilio's ever-decreasing pricing structure.

[aspired]

In my startup idea..each customer will have its own phone # and account. I was thinking of a service that can be hooked to customers existing phone # such that they continue paying their existing phone # and I can offer facilities on top of that. I am sure my potential customers are using land line and paying fixed money to get unlimited incoming/outgoing calls. But seeing charges of tropo/twilio it seems potential customers have to switch to pay minute by minute rather than fixed. I think i have to do a good research before I start this project. :)