This domain name may be fine for a forum/supporting team website/blog.
I don't think it can serve as a brandable domain name or as a platform for a business.
The only meaning of this domain name(the two words together) is that you or other entity want someone to reply to your/his previous question etc.(I would be happy to know if you had other thoughts as well).
My estimation is high $x to low $xx for an end user only.
It may take you a long time to sell it.
As for Resell value:$0
Next time you register a domain you must ask yourself "who will be my client?" "who and with what purpose will develop this domain?" Being a nice name is not enough, it must be monetized, there must be money involved that is the only reason someone would pay a premium for a domain, "the domain will help my business". The regular Joe who does not care for money and only is looking to make a blog as a hobbie will probably look for a reg fee name to start. TheNiceReply.com, ReplyWithStyle.com and ReplyXD.com are all available, why would someone with no wish to monetize a site would pay for an overpriced domain? Replyus.com in my opinion has little commercial use perhaps none and that defines the domain. Veredict: REG fee.