I like thrifting and antiquing too! We have a kitchen table my wife and I purchased at an antique shop when we first moved in together over 20 years ago!

It's certainly not the same experience, but have you tried bookshop.org for the books you're trying to find? This will allow you to buy from independent bookstores even when you order online. It seems like you'd rather support an independent shop like that than buy from certain internet retailers! I found some of the titles you're looking for at independent sellers there. I'm not certain about international shipping in case you need that, but it might be worth looking into.

Enjoy your thrifting and antique adventures!