Bookmarks - where to purchase, what to link to?

My book launches in one month. I have a bookmark graphic file ready to go, but I haven’t ordered any yet. Now I’m having these conversations about my book and kicking myself that I have nothing tangible to leave with people. So, I’m planning to order some bookmarks. The current QR code on the bookmark links to my newsletter (substack embed) sign up page on my WordPress site. At this stage, for something to leave with potential readers, would it be better to link directly to my Amazon account? Or wait until all my ducks are in a row and link to a D2D Books2Read UBL? (too many possibilities…)

Also, who do you typically order bookmarks from?