It's important to note that the numbers being thrown around mean nothing
'$800' isn't eight one hundred dollar bills or even 40 x $20 it's a
'voucher' good for very little.
You can't just turn around use it it for your next trip you have to meet
'certain conditions' as per the airline's wishes-this is known as
'fencing' and I have seen vouchers that are useless as teats on a bull because of it.
Is that one of those tours where you have to stay on the boat and cannot interact with anything at the site??
Galapagos tours are all like that-very tightly controlled on land anyway-maybe you could swim with Sea Lions but that's about it.