You can only make a profit when you instruct a class many times. To develop a class from scratch I allow 8 hours for every hour of podium time. Even a canned power point class from mike holt will have many hours in just setting it up. For a typical class I have done many times there still is about 16 hours - for registration, room setup, printing handouts, certificates, bank deposits...
Pricing is difficult - look at what other area providers offer. For some markets, IE in house classes, you need to charge more than your average contractor classes. Around here the going rate is $120 for 8 hours. Keep in mind you are competing against the internet providers - I don't do internet classes and don't worry about there lower cost.
I get by with a lower cost as I have a room that does not cost me much to rent. Expect to pay $250-500 for a hotel conference room. I also provide lunch as it keeps the class on site and I can go from 8 - 4:30 using 1/2 hour for lunch.
And one of the advantages of your own business is the tax write offs. Want to go to a mike holt seminar? deduct the cost, travel, etc.
Same with all your equipment. At the college you just get paid by the hour. I've been all over the country and to Alaska, all a write off.