How does one know which is the right business

I guess one does not know for sure which is the right one. Trying them all to find out is just futile. Everyday my mail box is filled with mail. Some body wants me to buy into their program. It's always the new best thing with lots of promises they cannot deliver.Yesterday, the mail man delivered the money book to my address. For responding within 7 days someone wants to charge me $299 for a manul and video that will teach how to trade commodity futures. Now, from what I know about commodities, one must have a margin account of at least $5000 but they don't tell you that. This little tidbit is very important. Let's say one buys the program and really studies it and put into action all the steps. Then that some one really wants to trade commodities and tries to open a real account only to find out that they must have some money in an account with the company they're trading unless they can trade it on their own. I know because I traded commodities before. The company I used one day called me and ask me if I would like to purchase 2 corn futures. At the time, they were trying to unload some of their bosses futures off me because they had some insider information that I was unware of. Being new and all in the market, I lost my money and never traded commodities again.