I would say start out with a pair of full foot fins from maybe mares if price is a concern. can get a decent model for under $100.
Canon 5D MK III
Canon 100mm L Macro, Canon 16-35mm L, Canon 8-15mm FE, Nexus Housing
Sony A7R2, A6300 Sony 90mm Macro, Nauticam Housing
Inon Z-240 Strobes, Weefine Video lights, FIT Focus lights