You'll find a lot of information about Croatian harbours and anchorages
on the World Cruising Wiki (Croatia - a Cruising Guide on the World Cruising and Sailing Wiki
), including pricing. From very recent experience, a typical Croatian harbour offers laid moorings, water
and electricity for HRK20 per metre (around £20 for your size of yacht), though the most popular places (e.g. Hvar Town, Milna on Brac) charge more. Buoys are typically half or two thirds of that amount, depending on location and popularity. You can see a map of bays where there are official mooring
concessions at www.wosamma.at - Bojenfelder in Kroatien - Anchorages in Croatia - Nauticka sidrista u Hrvatskoj - Campi boe in Croazia
only have to pay for anchoring
in bays where there are mooring concessions (although increasingly some harbour authorities are charging
for anchoring, at least in high season). Although a little frustrating at times, this makes sense, since it's not unknown for some parsimonious and inconsiderate skippers to drop the hook on the edges (or even in the middle) of a field of moorings, thus endangering yachts that have paid to be on a buoy.