I started this 6 month trip in Reunion and used there Saint Denise as a base for excursion to the mountain areas, Hell Bourg and Cilaos. Stayed at a camping place (booked at Airbnb) which was the cheapest option to stay on that island. If you stay longer, Gites (hostels/mountain huts) are also reasonable. Public buses are cheap and efficent. Food is reasonable in bakeries but can be quite expensive in restaurants. Some supermarkets have the most amazing things from France like fresh oysters or Brie from Meaux (for a price!).
It't a very friendly but expensive place with some good museums and some old colonial buildings. The mountains are really impressive, and a lot of quite expensive beaches with all sorts of watersports.
The last day I was a for me unexpected holiday, most restaurants and almost everything else where closed.