WTB Refractometer (Used is OK)

[Eienna]

I need to buy a refractometer next month if at all possible. Does anyone here have one they could sell me for $20 or under? Used is fine. If not, could you tell me what you think of this one? I might get it if I can't find one here.
Automatic Temperature Compensation Sea Water Salinity Refractometer for Aquarium, 0% - 10% & 1.0 to 1.070 S.G. DUAL SCALE Hydrometer By AdeAdvancedOptics: Science Lab Refractometers: Amazon.com: Industrial & Scientific