It only takes a little good information in one area to more than justify the costs of the whole course. If it's a business opportunity you shouldn't need to spend a lot of up-front money. In fact - don't spend too much money, period. You usually can't buy success. Your business should help pay for itself very quickly.
People go to the Internet for free Information.
Offer them useful information for free. This builds trust and helps establish your expertise. Everyone is an expert at something. The Internet can be impersonal - you must establish a relationship with your niche market. It's your most valuable marketing tool.