If there is astral heron and I play any reflection unit does it count as playing card?

No. Playing a Reflection unit token is not "playing a card," so it won't trigger Astral Heron or consume his discount.

Tokens are not cards (Rule 185), and tokens can be played without ever being cards (Rule 350.2). Astral Heron's trigger specifically reads "when you play your first card each turn," so only actual cards completing resolution count. A Reflection token — even after it becomes a copy of another unit — remains a token (FAQ #11371), and copying doesn't retroactively turn its play into a card play (FAQ #11575).

One caveat: if the Reflection came from a card you played from hand (e.g., Keeper of Masks, or the spell Mirror Image), that card is your first card and can trigger Heron — but the Reflection tokens themselves still don't count, and the [2][A][A] discount applies to the next real card you play after Heron's ability resolves (FAQ #11762).