Quite a few campsites,
Orchards Camping
Appuldurcombe camping
Windmill camping
and possibly more too, but will be super busy in July & August.
There is a couple of small sites (aire type facility) too and wild camping is a possibility.
There is a place just south of the airfield at Sandown where motorhomes are always parked, have seen them quite a few times.
The island is a lovely place to visit.