I can't imagine why a dive store would not give employees equipment at cost plus shipping.

The most important thing would be the added draw/benefit of such coupled with the morale boost this would give compared to profiting off your success team.

Additionally, by having your team members equipped with pro gear that may have higher margins, your sales may be positively impacted by having students desiring to purchase products they see your staff using.

To raise your employee equipment purchases prices 10% above msrp, then discount it 25% off that is a morale crusher and represents an attitude of fostering an adversarial relationship with what is supposed to be your key success team players.