Most of South America is actually very ahead when it comes to ecommerce/epayments/fintech so don’t feel the need to bring large amounts of cash before hand. Credit Cards, or simply using your phone and tapping the credit card terminal works in most places. In addition to Uber, I would download Cabify to have an alternative if Ubers are backed up. It’s big in LatAm (and Europe) and helps connects you with local cabs. Meitre is also another service i would sign up for given it’s popularity. It is essentially an OpenTable or Resy for Restaurants in South America.

Argentina
Brazil
Chile
Colombia
Uruguay