Questions about IG Phone verification

Hey! I have been planning to make multiple IG accounts and I have a few questions about phone verification.

Apparently there WILL come moments when I have to verify my accounts or I'll lose them.

So after a little bit of research I found out I either need physical Sim cards or some weird online number services?? (Do they even exist?)
Let's say I have 20 accounts. That means I have to buy 20 sim cards 10€ each. That can get expensive. So is that just what I have to do or is there a cheaper…

Questions about IG Phone verification