I have never found a buying group that was worth what they charge. When I took over my practice, it had been part of a buying group, and the first thing I did was evaluate what THEY did versus what I could do. I found that I could drastically lower my cost of goods, cost of advertising, cost of marketing, cost of administration, etc… By doing it in house. Best decision I have ever made. Within 4 years, I grew the practice from one full time office to 7 full time offices… 1 dispenser to 8 dispensers, 20 units per month to 200 units per month. ASP from $2000/device up to $3200/device.
I have found that buying groups just service to funnel all of your profits to them instead of you.