I think both names could have potential if they where put to good use.
I personally like nameyard.com. It has the name to be a popular domain related website; Maybe an exchange/trade domain based website or simply a place where people could pay a sign-up fee and hold their domains... If this domain was put to good use, the 'yard' part of the domain really opens the doors to a potential domain related website.
hostingsecrets.com would be a great domain for a website built up for the sneaky tricks and trades of web hosting business as a whole. We all know and have read peoples opinions on web hosting, and the sneaky back doors of it; imagine all that information gathered up and produced into one website!?
I'm no good at giving price estimates, but both domains do have potential if developed properly.