You can create an account in a "foreign" app store to download free apps, - this has been possible since forever....

If you want to purchase $ apps, you need to have a method of payment, you can do it buy getting gift cards from the applicable country...

Yep, you just change the store and then select a free app to download, and it'll ask you to create an account. Just decline to provide a credit card when it asks you for one, or if you have a OneSmart Mastercard it should take that.

Edited to add: I use my YouShop address and phone number for US and UK.