Not sure if this will help or not, but nearly every Internation airport I go through has free "sim cards" with a small amount of minutes on them in order to help you reach your destination. I've seen them in Germany, Thailand, Switzerland, Phillipines, Mexico, Panama, Belize, etc, as well as a few times I've seen them state-side (mostly LAX).
Have no clue if that will help, but it's one of the only ways I know how to get free sim cards. I typically stock up on them each trip LMAO
Depending on the site and how smart they are you might be able to use VOIP as well
As for warming up the accounts, just go slow. Try to act like a human

Take days off, don't do the same thing every day for 10 days in a row, etc. I've mostly had the best luck starting really small, giving a day or two break before I profile the account, then sporatically growing it from there i norder to prevent making bot patterns if you use automation
Also, I'd randomize posting if you use Automation. You can be as sporatic as you want, but if you bot adds something to your account say every 5 seconds, no human is that regimined, Humans are random and typically never click in the same spot twice and in the same amount of time. It's all about patterns