Hayley,
There wasn't to much time for say shopping other than souvenir sort of bits, while at Isla maroda there is a sealife place next door called theatre of the sea which quite a few went to, you can swim with dolphins or other animals if that's your sort of thing have a look online for prices, I choose to spend my money on a jet boat ride, myself and another lady hired a driver and boat it was fast and for me worth doing, that was from the hotel beach. I would say the driver was nice! So that was a bonus. I also paid to go on the conch train it was not expensive it was so hot no way could I walk to the furthest point in that heat...most of my money went on food, as only breakfast provided and perhaps 1 lunch or dinner, so budget for food per day you would spend here, some days might be cheaper others dearer, also the tour manager might have a few extras up there sleeve, we did a steam boat music evening which was really nice.
Have a look at theses
Www.edisonfordwinterestates.org Very interesting home
Www.sloppyjoes.com great place to eat and drink in Key West fantastic music as well
Www.tincity.com. Good shops and food
Www.conchtourtrain.com Key west much easier than walking
Www.napleshistoricalsociety.org Historic Palm cottage
Www.evsafaipark.com Everglades
There was an optional cruise 2 hrs cost $ 32.00, I have written $30.00 for the conch train, jet ride was $200 that covers 3 people and the driver it was 2 hrs, paddle boat was $30.00,
Take a debit and or credit card and have fun.
Hope that helps
Cindy