We wound up using TaxiTour Iguazú (Facebook link) for all of our trips in and around the Iguazú falls area during our two-night stay and they were fantastic! On time and friendly, we would definitely recommend Javier and his wife, Patricia, for any touring you want to do in Iguazú.

I had reached out via Whatsapp originally to book a driver for the Brazilian side of the falls, as taxis traditionally have an easier time getting through customs and immigration. The plan was a pick up from our hotel at 10am, take us across the border to the Brazil side of the falls, wait with our luggage, and then drop us off at the Agentina Iguazú airport before our flight back to BsAs. Once that was set, I realized we also needed a ride from the airport to our apartment (the bus only runs every hour), so we got that booked. Then, after reviewing the bus options to the Argentina side of the park and noting the prices doubled in the last few months to $12k per person round trip, we decided to get a quote for a return trip to the Argentinian side of the falls as well. To us, a private ride for double the price of the bus was an easy choice, rather than walk to the bus station, queue for tickets, wait for a bus, etc.

Airport transfer on Saturday evening (scheduled pickup): $25k
Argentina falls round trip on Sunday morning (scheduled pickup, on demand return): $50k
Brazil side of the falls, including border crossing, on Monday morning: $110k
Total: ~$159.50 USD (we paid in cash, Argentine pesos)