We wish we'd stayed at the Cataratas!
Our stay was at the Hotel Florenca, probably at 1/4 the price. The Florence is a fine hotel and there's not a thing wrong with it. Trouble is, it and all the other hotels except the Cataratas are outside the National Park, which opens at 9 and closes around 5 p.m.
If you're at the Cataratas, however, you can come and go as you please. You can take one of those priceless walks along the Iguasu at sunrise and sunset, when you'll have the National Park all to yourself!
We could have afforded the Cataratas if we'd had at that time the tip I'm about to give you now. When you go to Argentina, take a bus or a taxi, but not a guided tour. Not knowing any better, we paid more than US$100 for a guide to take us to Paraguay and Argentina. Recommended by our hotel, we thought he would be with us all the time and take us to those special little places that only guides know about.
Well, he didn't. He took us to the gate of the Argentine national park, dropped us off for five hours and went home. He came back at the appointed time, but had no suggestions of special places.
In other words, for all that money, we got three very expensive taxi rides that probably would have retailed for about a quarter of what we paid.
You do not need a guided tour to see the Argentine falls. Everything about getting around in the Argentine national park will be self-evident when you arrive. All you need is a bus or taxi to get to the entrance. (And, naturally, your passport. Check on the internet to see whether you need a visa to get into Argentina. From Canada, we don't.)
For that matter, in Paraguay, the shopping streets where we were taken are just across the bridge from Brazil. No special navigation techniques are needed. One caution though. We found Cidade de Leste, Paraguay, is a lot wilder and woollier than Brazil or Argentina. The cops in Paraguay carry automatic weapons, which they casually wave around as they smile to you. Although I don't usually like guides, I would not have minded having one with me in Cidade de Leste. Having said that, nothing bad happened to us, and the shopping bargains are incredible.
If you do get a guide in Paraguay, tell him you want to see things other than the tacky shops.
Happy travels, and let me know if I can help further!