Your Personal Survival Budget is the amount of money you need in order to live. It may be that you will not need to draw this for the first couple of months if you have money to fall back on, for example, a partner's wages, but the chances are your business is your livelihood. Keep your figures realistic. If you normally spend 40 a week on food, don't expect to manage on a budget of 20. You cost what you cost.
Economies are one thing but keep within the realms of reason.