If you want to text leads from a normal US phone number, the carriers make you register first. It's called 10DLC. It is a form, a few fees and a wait, and it is easy to get sent back.
You register twice. First the business, then the texts.
The business check costs $4.50 and usually comes back in minutes.
The review of your texts costs $15 each time it is read and usually takes one to two weeks. If it's sent back and you send it in again, that is another $15 and another wait. So a careless application doesn't cost the fee. It costs the fee two or three times, and the weeks.
After that it's $2 a month for low volume, with the first three months paid up front. A small team starts for $25.50.
Most applications come back for the same few reasons. The legal name doesn't match the IRS letter. The application doesn't show where people gave their number and the words they agreed to. The privacy page is missing one sentence, a plain promise that mobile numbers aren't shared with third parties for marketing. The sample texts don't name the business or say how to stop. Or the website can't be opened.
None of those are judgment calls. Each one can be checked by reading your own website and your own application before you send it.
Two more things worth knowing. Your daily limit belongs to the business, not to each number: T-Mobile gives a new business 2,000 texts a day however many numbers it has. And registered doesn't mean delivered. The carriers still read what you send.
The full guide has every fee, the limits by carrier, the sentence your privacy page needs and a checklist to run before you send: