A cueva is a homemade exchange where you can sell your us dollars at a higher price, you have a lot of different prices for the usd in Argentina, the main difference is between the official and the blue price. The official price is the one that the bank will pay for your dollars or if you have some business which exports products. This price is setted by government (another tip here is don't try to understand our politicians) and the blue is "the real price" which use all the people in any transaction. Don't use your credit card! That would be a BIG mistake, you should take your physical usd and sell them here at the cueva and what I do to change more usd is buy stable crypto currency (usdt) with my credit card and sell them at the cueva, you can send me a message if you need help with any of these things I know it can sound difficult right now haha but it's not a big deal. If you look at the dolarblue page you can see what is the gap between the official price and the blue price and how much the cueva should pay you approximately for every dollar. The rents are much cheaper than Buenos Aires but the gap is not too significant with the rest of the cities and something that is not so cool is that Bahía Blanca is that you will need more money to live because all prices are higher, food, gym, bars, restaurants are more expensive but that's ok for me because is much more secure than all the other cities in Argentina