As for tourist stuff, there are tons of "travel agents" every few meters. They're generally selling the same product and are 3rd party resellers of travel packages.
Generally you can island hop the area around or tour Phuket island yourself. For the latter, I'd recommend you just get Waze on your phone, google a few spots and explore at your leisure (rent car/bike and maybe bring your girl as a guide). There are tons of other interesting places just minutes away like Kata, Kamala and the likes. If you have a girl with you it helps with bargaining and general translating, especially if you're of farang decent.
Island hopping there's tons to choose from. Very affordable and includes hotel pick up and meals. I'd suggest you start with the Phi Phi tour (just a name, you'll see more than just 1 island).
Note: a tour i.e. Phi Phi island, island hopping day tour will still have several companies running the same tour. So this will vary by boat, food and tour guide quality; Also impacts prices. Try to get an agent that has personally been for the tour and preferably has actual pics. Also note, less ppl on the boat means more expensive BUT you'd travel with less hassle and see more stuff or can chill at your own pace. Else you might feel like herded cattle.
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