(feel free to provide or update the cities below)
Austin
http://allstexas.com/
Not the cheapest option, but we were only three students. Focuses a lot on speaking.
http://www.austinkoreanschool.org/
Typical saturday school for overseas Koreans who wish to see their kids learn Korean as their second language. They seem to exist in all big cities where a big Korean community resides. They sometimes provide classes for foreigners.
There is also the “Austin Korean language and culture group” on meetup. I can not add the link until I gain some seniority on this forum.