The best way to go around Makarska Riviera is to use Rent a car service. It is not too expensive, but not cheap also. When you decide to visit nearbye Brela or other small places along adriatic coast that is the best way. Even if you decide to go swimming out of Makarska, to some not so crowded beach that is again the best thing to do. The price include:vehicle renting, unlimited kilometers, Insurance, VAT 22%.
I usualy use service of one specific tourist agency in Makarska. It is called CROATIA TOURS Makarska and it is located in center of town on so called Riva (coastal line).
Reason why, is because they have online reservation and prices are very good compared to others. My favourite car is Citroen C1.
The only problem is that they are to busy during summer so there is possibility they have no cars free for rent, although they have many cars in their car park. Maybe they should get some more.
Have some off-road adventure, rent yourself a buggy (pics 1 and 2), rent a "family" bike LOL (pic 3) or just a bike for your favourite son (pic 4)