Diamond is usually ten times the price of cubic zirconia or CZ of the same carat and color. So, this is indeed understandable. However, similar to diamond, cubic zirconia is priced according to carat. The bigger the carat size, the higher the cost. But, there are ways to purchase cheap CZ rings these days.
Just visit a couple of virtual jewelry stores, which sell this kind of rings. Some of these websites provide drop down menus to make the search for what you want faster and easier. There are menus for price range, color, shape and other aspects of a ring. So, if you have set your budget when it comes to buying a CZ ring of a particular carat size, then, just choose the price range drop down menu.
You would be able to see a number of rings of the same carat size but with various designs, colors, shapes and styles. Depending on the website, which you visit, you might be able to see colors such as champagne, emerald, garnet and lavender. Since there are a number of virtual jewelry stores which sell cheap promise rings, shop around first before buying what you want.