Balto

Step 1: Registering a phone number -> I wanted the texts to come from a number and look as legit as possible. The oldest iPhone I could find still supported by carrier was an iPhone 4, so I picked one up off ebay $20.56

Step 2: Buying a SIM: I bought an ATT prepaid SIM, the cheapest plan was unlimtied talk and text for ~$25/mo

Step 3: Registering an apple id: I now went through the tedious process of setting up the iphone and making sure it had a source of power

Step 4: Find a Mac Mini: I used macstadium and bought a dedicated mac mini. It came preinstalled with Catalina, but I still had to install python, ngrok and deploy the server that would run on that machine (a tiny flask instance to interface with iMessage) ~$20/week.

Step 5: Build the public API. ~$7 a month on Heroku for a flask webserver.