Ask HN: Is Twilio too expensive for you?

Not sure if everyone is in the same boat, I made an app and one part of it allows you to invite your friends via text invite.

My users send about ~500 texts (each text is about 3 segments) and I am spending about $10 every 2 days. Note that I'm a sole developer and not a major company so dont have the funds to keep this up.

Is everyone else sort of in the same boat or have they been able to find some hacks that people are willing to share?

EDIT: Also if anyone knows any developer free offers, etc. that don't need pre-approved phone numbers for Twilio.