Dance shoes are generally not cheap. If you found something for only $40, chances are they aren't ballroom dance shoes or at least not good ones. My first pair of dance shoes cost about $80 and they weren't from one of the well known, top manufacturers. My second pair was and cost about $100 or so. You can use other types of shoes for ballroom, I think I've heard of people substituting jazz shoes, but I kind of doubt you'll find a good pair of ballroom dance shoes for only $40. But I am talking about new shoes. If you find someone selling a pair they bought because they don't fit right or something then you can get them for somewhat less. Used (almost) always costs less then new.

--
James Marshall
marshall@astro.umd.edu
http://www.astro.umd.edu/~marshall