From what Russ is saying, it seems the cardboard sextant would be quite sufficient for your course in the great maritime hub of Colorado. Save the money for something else, like a GPS.

On the other hand, if you want to have something to show off to friends -- and I suspect this may be the case, because even I want such a thing -- then perhaps Russ (or another seasoned seadog) can recommend something with that in mind. It's gotta be decent enough for learning, and it should look good next to a musket and a triangle hat. Come on, just admit it!