Ask HN: Monetizing SMS?

I'm building a side-project app. One of the main features is that I send out some information on a weekly basis through Twilio. Ideally I'd like to find a way to offset the $0.03/SMS cost through in-SMS ads - and if I could make a buck or two in the process I wouldn't mind that either. Are there any SMS ad networks? Note that I am currently only support US numbers.

I'd also consider alternatives. For example, I considered the free email to SMS gateways via the US carriers, but they seem inconsistent.