The cost of getting married is minimal. You have to buy a kesubah (but you probably can find one online you can print yourself). The Kiddushin should cost much since it is a halachic inyan not to get something that a reasonable kalah would be able to evaluate (and apparently a head of lettuce will do, if you are desperate). A government license is helpful for paperwork purposes but probably not required at least states that have either “common law marriage” or who regard the “license” as a revenue measure but not something that affects validity. There are no community regulations on minimum size for a dowry.
Of course, most young people like to make the wedding fancy. And the standard of living in America is so high, they are able to do so. Our ancestors would be amazed, and probably somewhat envious. However there is no halachic requirement to spend a massive amount of money getting married.