Time to update our financial picture. Here is the breakdown and summary by country:
Trinindad & Tobago: $109/day average. TnT is fairly expensive, with lodging really tough to find for less than $35-$40/night. We also spent money on the flight to/from Tobago and on renting a car for a couple days. Overall, our spending here was fairly even, though, so I think that's about the right amount. Note that food is overpriced in Tobago because they are an isolated island. We ate several peanut butter and jelly sandwiches to keep the cost down.
Venezuela: $90/day average. $50/day without the trip to Angel Falls. We think the trip was worth it, though. You have to use the blackmarket or these numbers would be 3 times as high. We normally paid $10-15 for a room and about $3-$4 each for a decent dinner. Transportation is nearly free because gas is nearly free (we paid $11 each for an overnight bus for 13 hours and the buses are way nicer than American buses). Angel Falls costs $250/person, though we wish we would have found an operator that would throw in a free hotel the night before and after, as many of them do. In Santa Elena, we suggest Francisco at Touristica Alvarez at the bus station. He did a good job getting us a tour in the Gran Sabana, though you have to be flexible with everything.
Guyana: $70/day average. Skewed by us hitchhiking the length of the country rather than paying the high bus fares. We sort of wish we had visited more of the interior, but we couldn't afford the very high transportation costs. We met people who often spent $300/person just to get to some of the inland places. Mostly, I wanted to see giant anteaters, but maybe somewhere else. Lodging was consistently $30-40/night and you should bring your own food to the rainforest or be prepared to pay higher prices for it. Food in Guyana, especially local food, seemed almost free. One morning, we bought every bit of street food and drink that seemed at all interesting until we could barely move. It amounted to about $4. We did have a bad experience going to a Rodizio suggested by our book. It ended up costing about $30 and was not very good. Don't go to rodizios outside Brazil, I guess. Oh, and lastly we decided to skip Kaiteur Falls. They looked very nice and I would have loved to do the overland hike to them, but it was $800/person, which seemed crazy for 4 days.
Suriname: we're on track to average $190/day. Suriname, mostly because of transport into the interior, is really expensive. Paramaribo is also very expensive. Rooms for less than $35-40/night are really hard to find. Meals aren't as expensive as the US, but average about $7 for a standard restaurant. We're taking a cheap tour that doesn't go that far inland and it is $300/person for 3d/2n. The ones that really go to the more interesting parts start at about $700 for 4 days/3 nights and most are even more.
Feel free to ask if you have any questions. Our guidebook is woefully out of date for the Guyanas, so expect to pay a lot more than many books indicate. We've learned a lot and are happy to share our knowledge if useful to anyone.