The question of prices is complicated by your market: if you're the only Op in town, that's one thing, but if not go have a look at what the other guy's doing.

For reference: In Oz, most of the machines were AU$1/play or more. In the big arcades they usually ran off a card system which had 'member's pricing' and bulk-buying discounts, but the label price was higher, say $1.40-1.50, and it often worked out to random-ass number like $1.32. You could often get time-play cards as well (unlimited plays for an hour, or whatever). Elsewhere they often had $1, 3/$2.

Here in Japan, neverland is ¥100/game, 3/¥200 on pre-stern DMDs, and 2/¥100 on EMs (on 3-ball play), but no matches and replay scores that are off-the-charts. Silverball planet in Osaka has prices from ¥10/play on beat up old EMs to ¥100 for new stuff. (The dollar is about ¥110 at the moment.)