Indo-Scythian, and not nearly that old. Worth maybe $10-15. Btw, there are NO coins 1800BC, the first ones were minted around 720BC.
Not Indo-Scythian in the strict sense, but Post-Gupta, Maitraka of Valabhi, later type. These copied the design of the Western Satraps (Like also the Gupta did). Only dynastic sign on the reverse is a trident. These were made over a considerable time span, and also copied extensively after the fall of this dynasty as means of payment. Over the years the design degenerated considerably. This one is fairly nice. Agree with the given value for US market, but as you get it from India 5-7 dollar max. This is an earlier specimen of the same type:
