There is no simple one answer. It depends upon your product. ( the nature of the business. Some of them do not need much money such as seasonal business for example, but others do need).
You should focus on cost benefit analysis, and find out BREAK-EVEN POINT for your product. And then everything has to be based on this. Check cost accounting on pricing issue. However, there are several ways to price your product. Speaking Ad expenditure you need to use cost accounting techniques. First find the break-even point and then let me know.
