I can tell you that it costs more to bring in your own ball than it does to purchase one from your pro shop. First off, the service you receive from your pro shop normally is far superior than buying stuff off of the internet. Some sites won't allow you to request specific pin placement and top weights. Also, when you buy locally from your pro shop, if anything were to go wrong with it they will do all the warranty work for you. You buy it off the internet, you are playing with fire. Even though the pro shop you took the ball to drilled it, if there are any issues with it, your pro shop guy/woman won't take up on the warranty issues. That is something the bowler must do. The best thing is to purchase from your pro shop and not from an online retailer. You will end up paying the same if not more for them to install the grips. Just because you have your own grips, doesn't mean all it is is dropping them in the holes and thats it. There is cutting them down. Making sure your thumb is correctly done. I would say it would cost about %65 bucks to bring a blank ball into a shop for drilling, grip installation and or grips and installation.