I'm a wireless consultant who has routinely trained people (end-users) on wireless technology and products on behalf of my previous employers -wireless equipment manufacturers.

I have spotted an opportunity create a training business which, as a start, can provide cost-effective, vendor-neutral training designed to enable end-users to avoid common (often expensive) mistakes, make better technology choices, and reduce their dependency on equipment vendors and their reseller partners who often offer their preferred products, which may not necessarily be the best or even appropriate solution.  

The training isn't intended to turn them into experts but to help them identify what they don't know, but need to know about the technology and practical advice on what they need to do, or to avoid.

The typical end-user clients are typically, IT managers or facilities managers across many sectors including: local government, schools, colleges, hospitals, offices, retail, logistics etc. The courses would be held routinely across geographical locations and major cities offered to individuals and groups from across different sectors.

Does anyone have advice or ideas on how to reach the target audience without expensive marketing or excessive unwanted spam or junk mailing?