I am not quite sure what you mean by up sell. Correct me if I am wrong, but I am thinking that you mean, different prices or higher prices on the same system. Let's see if this makes any sense to you:
I have a system that can handle about 200 people, so for example I charge $500.00 for four hours.
A client comes to me and wants me to do a function for 400 people, so then, I recommend a larger system for $700 for the same four hours. This is what I will call an upsell. I suggested a different category/package system for the larger event. Is this what you mean?
The initial posts were about a dj making a pretty substantial, maybe even massive upgrade to the size and or quality of his sound system, and then raising his package rates overall to offset that purchase, and they were asking around how one might go about spinning, justifying, and getting clients to pay those increases.
The general consensus so far seems to be that that kind of increase is not the best way to capitalize on such an investment in equipment, which is an investment that should be made with full knowledge that it will pay for itself over time rather than in a few months by tacking an additional $500 onto their current rates.


