Well, with $6.59, I can buy 13 chocolates (assuming no fractional chocolates are sold), with 9c left over.
Now I have 13 chocolates and have 13 wrappers, with which I can get 6 more chocolates.
Now I have 6 more chocolates and 7 wrappers (one wrapper left over from the 13)
Now I get 3 more chocolates and have 4 wrappers (one wrapper left over from the 7)
Now I get 2 chocolates and have two wrappers.
Now I get 1 chocolate and have one wrapper.
Assuming I cannot get 1/2 of a chocolate with that one wrapper, I have a total of 25 chocolates.
If fractions are allowed, I could get an additional chocolate with the one wrapper, but it would take an infinite number of transactions. Similarly, I could get an additional 9/25 of a chocolate with the 9c, if fractions are allowed.(Details on request)