How can I charge people money who text into my keyword?

Unfortunately, TextMarks does not support any sort of thing where people subscribing to your keyword are charged money to their phone bill. This includes ringtones and donations. In the industry, it's called "premium SMS". Typically in these deals, the cell phone carriers take 50% or more of the revenue, so we've had some customers use TextMarks to accept bids or provide links to payment pages.