You're correct, the breakdown for a monthly SMS fee is $500-$1,000 (for a 'vanity' short code) just to hand on to the name (think of it as paying $500 for a domain name of a random sequence of characters or $1000 for a domain of your choosing).

It doesn't stop there thought. Typically you have to pay an aggregator to send and receive messages from the cell networks. This usually costs thousands of dollars and is broken down between a monthly fixed cost or a cost per message (typically $0.04-$0.05 per outgoing message or $0.01 per incoming message).

But that's not for fund raising short codes. If you're a corporation, the cellphone companies take anywhere from 50%-75% of the amount that is to be billed to the customer; however, this number is much lower for non-profits. The caveat though is that not many non-profit organizations are approved for these lower rates; companies like mGive and MobileCause have to do a lot of work to get this clearance from cellular phone companies and act as an aggregator for non-profits.

Oh, and there's one more thing: the application process, which is a fucking nightmare. It takes 3-6 months to get a non-charging short code and thousands of dollars without any guarantee of approval. Worse yet, each cellular network has to approve of your application so if all US cellphone companies approve, but one like Verizon says, "No, sorry," you're screwed. When our company went through this process, one cell provider said, "No," at first, and then asked us for a sample of the SMS messages that we would send and receive.

Net net: its a fucking mess out there in the SMS short code world. If you want to see what a world of non-net-netruality looks like, look no further than cellular providers.