1- price out your market area. Have a staff member, or yourself, call different practices in your city/town, and ask for pricing and particularly what is included and not included in this price. This will give you a bench mark of where your competitors are. I found that including MORE in services for a similar or slightly higher price works well.
2- Price on the higher end, but start out running a fabulous Grand Opening promotion. This will help you lure people in and establish clientele at a reasonable price, and will also give you an idea of how affordable people think it is. If the sale price seems like a stretch, you can keep the promotion running. If it's an easy sale, you can end the promotion and then reinstate it during times when business is slow.