This is a crucial question when you go to Galapagos, because you have to take a boat cruise. It is impossible to really see the wildlife if you stay only on inhabited islands like Santa Cruz or San Cristobal. You should take at least 5 day cruise to really see something. Now the most important question. How much? If you see in the internet the price of 3000$ for a 5 day cruise it is ridiculous, and the they just want to rip you off. So if you can don’t book via the internet. You may try book in the main land of Ecuador like in Quito. The best place to book your dream cruise is actually Santa Cruz island on archipelago, you just go for a walk in Puerto Ayora from one agency to the other and look for last minute occasions. We paid 1100$ but everything up to 1400-1500$ is a fair price. Good luck!
In my portfolio you can find some photos from my Galapagos visit.
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