Unsure how reputable this source[1] is, but suggests that discovery alone (i.e. getting all the pre-trial evidence / arguments in the open) can be upwards of several million dollars depending on the size of the lawsuit. Obviously its smaller for something like these Yoga classes - but if the process is 10-30k, and you're only bringing in 10k a month, it could easily put you in the red.
[1]: http://news.cnet.com/8301-32973_3-57409792-296/how-much-is-t...