I'm in the US, I have two 20-year old phone numbers and 1 cell number, none ring through with span or scams.

I wonder why that is? I dont give the numbers out. That's why. Whenever a store says "do you gave a number with us" I say I don't have a cell phone. If they can plainly see I do have a cellphone, I add, "for that."

The second part is shopping at stores that dont tie prices to your having given them a number.