The bowling center owns the shop I drill in.  The center manager sets prices,all of which include drilling but not grips and slugs.  Only she can offer discounts and she seldom does.  I like it this way because I don't have to get involved in haggling, I just send customers to the manager.  The shop is considered a convenience for our bowlers, not a profit center.  Pricing is low on plastic balls ($64.95), competitive on mid-line balls, and high on top end balls ($220 - $240).  This structure encourages the junior bowlers and new bowlers to buy their own ball.  We stock plastic balls and a few entry level reactive resin balls and special order the mid line and top end balls.  We have set what I consider to be a competitive price on drilling internet balls, $60 + tax which includes a slug and finger grips.  I give the same service to those who choose to buy over the internet as those that buy from the center, but no warranty protection other than on my work, and then only to fix any mistake I make.  The closest shop to ours is about 40 miles and if customers want to go to that trouble to get a slightly lower price that's fine, just don't expect me to do free work on those balls.  For our customers I do most surface work at no charge and provide help with their game if they want it, also at no charge.  --  JohnP