Looks like some Anker power banks are on sale again. Last time this model was posted (about a year ago) it was just over $36; now it's only $29.99. Black and white colours are on sale (thank you vbhlsd).
Note that if you use a case the case needs to be MagSafe compatible as well, or else this won't stick.
Compatible Devices: iPhone 16, iPhone 16 Plus, iPhone 16Pro,iPhone 16 Pro Max, iPhone 15, iPhone 15 Pro, iPhone 15 Plus, iPhone 15 Pro Max, iPhone 14, iPhone 14 Pro, iPhone 14 Plus, iPhone 14 Pro Max, iPhone 13, iPhone 13 Pro, iPhone 13 Pro Max, iPhone 13 mini, iPhone 12, iPhone 12 Pro, iPhone 12 Pro Max, and iPhone 12 mini.
Shows white on sale for me.