Custom golf netting solutions can be calculated quite easily online by using the tools provided on different websites. Not all of the golf barrier netting companies are going to provide this feature, but I'm on one site right now that lets you enter the height and width to give you a good idea as to what you're going to be paying.
Of course, you'll have to get the firm quote directly from the company. It's still cool to get a general idea or quote before you have to start talking money with the company.