The coralife thermometers I buy locally for $10.99, but in helping another member (who PM'd me) find these, I saw Big Al's has em for like $6.99, plus shipping.
Drsfostersmith.com happens to have a sale on their Drs. Choice refractometer, which sure looks almost identical to my Premium Blue refractometer (that's the only name I know it by). They have it for $42.99. No build in light, but I've yet to have problems reading mine off a 40watt incandescent. Sometimes I use the lights off my 75gallon...makes for a nice sharp line on the scale.
In fact, I was telling my wife about this thread over lunch, and it dawned on me, that the electronic TSS meter could lose its calibration, and probably involves a fair amount of work, or sending it back to the manufacturer, to re-calibrate.
To re-calibrate your refractometer, you need 3 drops of ordinary distilled water.
Former advisor and planted tank geek...life's moved on though.