A tip if you want to take some longer day-trips to the popular activities - like Mayfield Falls, YS Falls, Appleton Rum Factory, Black River Croc Tour, Floyd's Pelican Bar, etc.
Suggest you contact some of the established tour companies and tell them you'd like to be an added person to go with a group already going. That way you're not paying the whole cost by yourself. For instance, instead of roughly $130 for the day by yourself (or for 2 people) + tip of course, most tours are just $20-$30/person extra for more than 2 people, and you could divide the total cost evenly.
It's pretty common, and the tour operator will make sure the others are fine with doing it. If you're flexible on the day, and give them a list of places you're interested in - I'm sure they'll be able to match you up for a couple trips.
Two that I see doing this all the time are Talk of the Town Tours and Clive's Transportation - both highly recommended on this site. I am sure there are others. Clives even has his prices posted for the various tours - and of course they both will setup custom trips.
http://www.talkofthetownnegril.com/
and
http://www.clivestransportservicejam...ingtours_1.htm