Opportunity cost, skills to carry out the business and most importantly will power. Money, don’t worry, you will have it after you start unless your business needs huge investment. If you have a doubt that you will not be making the salary amount from your business or even half of it then don’t over think it.
Don’t give a damn on your salary amount give a thought on how to earn more and how to run the business. Develop ideas on using the resources available around you. The sacrifice or insecurities will give you a boost for better you. Believe in what you are willing to do without it do not dream of becoming an entrepreneur.