Nominalia.com has this limited offer for one more week (until 23/09/2019): 2 registrations at 0.9 euro each- just for EU users, if I understand correctly. Important: basic price there is quite huge, so this is suitable just for registering 2 domains and in less than one year transfer them to your favorite registrar (go daddy, namesilo, etc). Promotion is for registration only, not transfers from other registrars! Enjoy!
One .com at just 1$ at https://www.ionos.com/domains/1-dollar-domains . Same at nominalia, the offer is available just for the registration fee, renewals are (I think) 15 USD. Not sure of the duration of promotion.
Epik.com offers promotional .com register prices till end of September : 5.49 eur/domain, regardless of how many you register. Disclaimer: I’m not yet sure if this is for namepros members only or for anyone!