My wife and I will be traveling to CR for the 2nd time. We did not see the Osa peninsuls the last time we went. We're not sure whether to go to the Drakes Bay area or the Puerto Jimenez area as a base. We will not be driving and we prefer not to pay those high prices that the lodges charge in that area. We would like to do some exploring of the Corcavado area, but not more than day trips. We will be moving on to other areas after our visit here as we have 3 weeks to plan. That's what were trying to do now. Any advice would be greatly appreciated.

Not much in the way of day trips except hiking in Corcovado and the surrounding area but there are two tent camps in the Carate area. Still pricey but less than many of the lodges. They are Corcovado Tent camp which is run by one of the top tour companies in CR. The other is the La Leona tent camp run by a great family from Ohio who are from a little town just south of where I live. Have stayed at the Corcovado camp and enjoyed myself although privacy can be an issue because the tents are pretty close. Food is always good at the Costa Rica Expedition places.
For a place further from Corcovado but just outside of Puerto Jimenez where you could do some day trips you could look at Pearl of the Osa. Very basic but clean rooms with fans and a good breeze. Owned by Toby and Lauren who also own the Iguana Lodge next door. The downstairs is a public restaurant and bar and can be fun. It is right on the beach. The food is very good. There are also some less expensive places closer to Pto Jimenez.

Thanks Suzie for the advice. If we were to stay at The Pearl how long in travel time to Corcavado? Is it reasonable to make a day trip to here from the Pearl and back after a day of exploring the Corcavado? What about down in the Matapalo area? Do you know anything about the Casa Bambu? This would be closer to the Park also. Thanks.

Do a search for Casa Bambu. There was some discussion about it not too long ago.

It is about an hour and a half on a very bumpy dusty road to Carate which is the end of the road. From there it is another 45 minute walk to the La Leona entrance to Corcovado. Basically 45 min to Cabo Matapalo and 45 minutes from there to Carate. Look Out Inn is a very nice place at the end of the road and we just love Lana up at Luna Lodge. Unless you got up very early to catch a taxi to town and rode the colectivo for just a couple of dollars, it would be pretty expensive to hire a taxi to go back and forth. The colectivo returns to PJ around 5ish.
If you were to stay in the Cabo Matapalo area you would most likely see many of the same things you would see in Corcovado. It is all the same area except that some is developed and some is preserved.
I have walked by Casa Bambu several times and it seems like a very nice place. Looks like a place that I would definitely like to stay. A little more down to earth than some of the more expensive lodges but you can even eat at the lodges rather than cook your own meals every day. Also a great place for fun is Martinas. Just a fun little bar nearby.