Today, I found two volumes of a Power Pack Classics trade.
Volume 1 collects #s 1-10, and therefore includes the Marrina appearance.

I plan to get volume 2, since I have all the issues in volume 1 and want more. (I've been after Power Pack and a bunch of 80s titles.)

- Le Messor
"I didn't say that I'd never slay another vampire. It's not like I have all these fluffy bunny feelings for them, I'm just not gonna get way extracurricular with it."
~ Buffy