For one person? Good food and local transportation, though not nearly as cheap as 4 years ago, are still comparatively inexpensive. One can get along quite well on $100/day. That would allow good (not fancy) meals , plus the normal complement of Uber/taxis transportation, with an occasional non-touristic show, e.g. cafe Tortoni, Centro Cultural Borges, Torquato Tasso. Consult guiaoleo.com.ar - a decent Zagat like resource for restaurant info. You can lunch/dine well for a lot less than $25 per meal. Check out my fav local spot - Bar Norte on Talcahuano.
Moreover, if you're smart on breakfast and lunch (many places offer an executive lunch for about $10), you should be able to include a more touristic tango show ("drink" show, not dinner) at a decent club like Tango Porteno or Madero Tango.