Cozumel: Port shopping area has plenty of souvenir shops. You can bargain heavily at some of them especially the ones upstairs above the duty free ship. Those vendors up there will have guys at the bottom of the stairs trying to entice you up there. They are desperate so you will be surprised at the hard bargains you can drive up there. We bought a hand made leather purse for $70 that started out at $120. I probably could have gotten it for $50 if I held out a little more. Take their price and offer half and negotiate from there. Start to walk away and they almost always drop the price more. You can get a voucher on the ship for a free taxi to the downtown shopping area. Cost you about $8 to get back. Loads of shopping and restaurants down there. Be careful of the sometimes confusing currency conversions as they are often in Pesos or may try to hide high prices with a free appetizer.
There's a Senior Frogs place at he port shopping area. Real fun and energetic place with games, and music. You can rack up a huge tab in almost no time there. A girl came by and offered some weak shots at $7 for two. The next thing you know, she's pouring 6 shots between you and yours and you're $21 in the hole without even blinking an eye. The giant funnel drinks are very expensive and you would think one would get you buzzed but it's very weak. You could drop well over a $100 easily. Food is decent.
Bring good water shoes and you have to hold hands in a long chain all the way up and it takes about 1.5 hours to make the total climb. Water was chilly but refreshing and clean.
Great excursion but took the entire day. Didn't get back until 10 before all aboard so missed out on doing shopping.