Digikey has the modules for under 4 EUR in unit quantities, but they aren't the friendliest to integrate, since they only have pads on the bottom. I also found some boards with the bare chip for just over 4 EUR there, you can also find similar ones on AliExpress.

Nice, thanks! I didn't find them a few days ago when I looked, and I spend $40 for 5, when I could have gotten 10. Thanks again.