How can I experience Yasuni National Park on a tight budget?

Cuyabeno is probably going to be somewhat cheaper, but you're not going to get to visit for $10/day, or anywhere near that little.

The 'rule' tends to be that biodiversity increases as you move deeper into a forested area and further away from human habitation. You will still plenty of biodiversity in Cuyabeno - we stayed in a good lodge there and probably paid $200 each for 4 days, which was well worth it considering the service we got and the fauna/flora we saw.

Don't confuse biodiversity with abundance. The biodiversity of the Amazon basin is huge, but you still have to look for wildlife - you won't find the trees thick with monkeys or the air with macaws.

Incidentally, I'm interested to hear how you manage to live anywhere in South America, outside Bolivia, for $10 a day. Do you spend every night in a tent? For Argentina and Chile even 3 times that is still pretty shoestring!

So, the two person consensus thus far is that Cuyabeno is less expensive. The $200 4-day trip sounds doable but there's no way I can afford $100 per day for a lodge + $100 per day for a tour. #1, through whom did you book your 4-day $200 tour? #2, you mentioned cheap jungle tours may be had by hiring a guide and sleeping in hammocks. I'm certainly open to the hammock lifestyle...do you know of any such budget tour operators/guides in east Ecuador? Thanks for the feedback!

Just to put the $10/day claim to rest (Yasuni vs Cuyabeno is crux of the thread), I can make it on $10/day when camping, staying with friends, or couchsurfing in places like Central America or, yes, India seems to be the cheapest place in the world to travel. I understand that everywhere is different, and that $10/day isn't a possibility in the Ecuadorian jungle. I'm just looking for suggestions on how to make it as inexpensive as possible.