Well, I put one together from a kit years ago. Gave it to my l'il brother. I think the kit was maybe $80. I put a fair amount of elbow grease into it, but I doubt if it is worth over $100, if that....
Steel or brass frame? Replicas don't hold their value very well but the steel frame guns bring more than the brass frame ones do. I've sold steel frame guns in the 150 to 200 range, usually can't get much over 100 for a brass frame gun. I know that current production replicas sell for a lot more new but you're not likely to get much more than that second hand.
CVA guns were on the lower end of the quality scale. They're not Uberti's!
I've seen some stamped SPAIN.
As others said , the brass frame guns were mostly for decoration. I'd probably give $50-75 if the case was nice. I'd hang the pistol in a tree and put my Colt reissue in the case.