Just go straight to the local bookstore's website. A lot of the stores on bookshop also have an online store. Bookshop is a supplement and basically just plugged straight into Ingram (the distributor), so they're able to sell whatever your local indie's web store lacks.
So, if I'm going to order online I'm happy to do it in a way that supports small bookstores.
I imagine there are others like me.
Local shops offer human curation instead of algorithmic recommendation, and create situations where you can stumble into something that you would have never even thought to search for.
If this isn't a way you like to shop that's fine of course, but it's something that a lot of other people enjoy. Personally, I loathe algorithms that recommend things to me based on what I've already consumed, and certainly hope we don't ever lose our local bookstores.
also, local bookstores tend be an integral part of the local, geographic community, where you can engage with likeminded folks who live nearby. amazon can't do that in 2020.
and, amazon has so much power that they force publishers to offer lower prices. that's bad for your margins if you're a publisher and causes the quality of book to go down since they're gonna want to sell more of what sells. what sells well doesn't necessarily mean better quality. i don't want the good publishers to go out of business.
and! amazon can't do readings and book signings. if you're not into that, then ok, but book signings are very important for a thriving literary culture.
keep buying on amazon if you want to save money but consider throwing a few bucks to your local independent from time to time, please
It's arguably comparable to paying extra for fair trade products.