Audio Technica AD-500X Open Over-Ears for $69

It may feel like there are few options [and there are certainly a lot fewer compared to closed-backs] but you do actually have a handful of options for wired open-back over-ear headphones under $100.

Case in point this limited time promotion at Massdrop, they are offering the new condition wired Audio Technica AD-500X Open Over-Ears for $69. Shipping is free with orders of $100+

There is no mention of warranty in the listing.

Note that this is estimated to ship at the end of August 2022.