Everything I see in NY state tax laws applies to commercial or retail businesses. I am not a retail business. As an individual, items I buy from out of state, but used in NY state are subject to a use tax, not sales tax. The notion that I have to collect/pay sales tax for a garage sale is a little silly, and not enforceable in any way.
Here is the use tax info for my state. It's pretty interesting what can be taxed.
https://www.tax.ny.gov/pubs_and_bulls/tg_bulletins/st/use_tax_for_individuals.htm