Scale wise, the Macross kits were made in 1/200, 1/100, 1/72 and 1/48 scales. These were made by Bandai, Imai, and others. Hasagawa recently started making Valkryes in 1/72nd scale with all of the detail you expect from them. You can find these kits on ebay all of the time. Just search for Macross or Battletech under models. The larger kits go for outrageous (IMHO) prices but you can usually get a smaller scale kit around $20. Also, check your local hobbyshop as they may have some of these gathering dust in the back. One of my shops carries some of the 1/200 scale kits for under $10. It was also recently announced that Bandai will be rereleasing several of their Macross kits so check out Hobbylink Japan for more info. Greens models also usually has some of these kits for sale. The names on the kits are the names from the original Macross series (ex. Gluag Pod is a Marauder) so it pays to look at the pictures to decide which mechs you want.
Good luck and Good modeling.