Sales Taxes - When did you know that you had to collect sales tax?

As I keep reading more and more about collecting sales tax and there seems that there isn’t a correct answer. So, for the people who have started collecting sales tax, when did you know that you had to start collecting sales tax?

Yes, because if I have a Print on Demand store, should I only collect sales taxes from orders in my home state or should I collect them through all states due to where my potential customers live?

I have really been promoting it yet, I was getting somethings together. But tomorrow is all about promoting. I have a freebie that I think people will like and hopefully share as well. How is your store coming along?

I am in a few discords where I am think about promoting it which each have close to 10,000 members plus I was going to use some Facebook groups that I am in to see if that would work to. I did a calculation of all the people and gave a rough estimate of the amount of duplicates, and I can probably reach over 100,000 people. So if I can get a few freebie signups with these methods I will be fine. How long have you had your store?

Offering a freebie isn’t a good idea? What is the best method? I am always open to tips and suggestions.

Like digital ads?

It sounds like a great idea, but is it costly?