Can I come in your suit case?

I don't take up much room!
Don't know if this will save you $$$, but I suggest talking to the travel agents at
www.traveland.com. They specialize in EZE and booked our flights / hotel to Iguazu last year and they seem to have connections down there.
As you may know, there is only one hotel in the park on the Argentina side...the Sheraton. It is $$$$ and the quality of a "Holiday Inn", but the advantage is that you get to enter the park and stay later than everyone else. Also, you don't have to walk about 1.5 miles from the visitor center just to get to the falls. The downside is that you are basically stuck at the hotel (need to eat the crappy food there) unless you want to spend more $$$ to go into town.
Are you going to take your chances and try to sneak into Brazil? We stayed on the Argentina side and were able to see the falls just fine. Please do take a boat into the falls...and hike the small island in the middle of the falls...what a BLAST!
Have a great time!