Apologies if this is in the wrong forum, but I dont know where else to post this question.

What I want to know is, how does the whole sms/text thing work. Ok-ok, I know that is very vague............. For example these guys selling ringtones for your cellphone..... all you have to do is send an sms tot a specific number and they then send you a ringtone right back, or supply a link where it can be downloaded. These sms's always cost a fortune. My question is: How do they (ringtone providers) get their money? Does the cellphone networks "collect" their bit and then forward the rest to them - like commission? An sms would perhaps normally cost $1, but they charge $5 for their service (providing ringtones). How do they collect the $4 profit they make?

Is this type of a business easy to set-up?

Once again apologies for this vague question, but its something that has always bothered me.

Have a great day,
LL