First, i agree with OMS asia, it is IMPERATIVE that you get the appropriate training. Rebreather diving is very unit specific but i assume you already know that. Have you taken a Dolphin class yet?
I like my Dolphin. It's a nice unit for your basic SCR IMO. I got mine two years ago for a little under $4000.00 out the door. For that price i got the class, the basic unit with nitrox tank, the tank has a non-standard valve, the ppO2 monitor, the half fill adaptor for the CO2 scrubber canister, the EAN32 orifice, and a box of Drager Dive-sorb.
You need to find out what is included with the rig to determine what it is worth. One other thing i'm sure your aware of is that you will need a pony bottle of reasonable size for your bail out system.
Good luck & dive safe