My most recent PCE purchases were Populous, Daichi-kun Crisis, Detana! TwinBee, Energy, Outlive, Gaia No Monshou, a System 1.0 card and an Arcade Card Pro.
The Arcade Card Pro ran me almost $30. The rest of that stuff was less than $4 each, the 1.0 card was $1. The only choukusoge there, IMO, was Gaia No Monshou and maybe Energy. I don't usually see Energy as choukusoge as much as just "an MSX game".
None of this came from eBay. Some was from the MGC, some from friends, and some from Japanese junk shops. All are complete except maybe the system cards (don't have them yet, I'm betting they are lose).
So my point is, its not expensive. Its not as cheap as 2600, but nothing is.