Adorama offers its VIP members the Apple Thunderbolt to Gigabit Ethernet Adapter, model no. MD463ZM/A, for $29.99. (Not a member? It's free to sign up.) A $12 mail-in rebate drops it to $17.99. With free shipping, that's the lowest total price we could find by $10. This adapter provides an RJ-45 (Ethernet) port. Deal ends June 30.