I would say 0$-20$ it really depends on the numbers in this case. For example 888A.com could be worth 20$ or more. 516A.com I would say 0$ In general its not good to mix letters and numbers. Chinese like NNNNN domains but if you do not understand chinese then it can be difficult since the numbers often represent words. I think I a domain with 88letterletter for around 10$ on namepros.