It varies so much depending on the business that this can't be answered.
It depends entirely on your transaction size, margins, cost to acquire a customer, and customer lifetime value.
It takes a lot more capital to earn $1M selling widgets for $1 each with 10c profit than it does to earn $1M in sales commissions on $20M real estate transactions.
To figure this out, you need to put together a spreadsheet with a business plan for your own business, including product, marketing, and overhead costs; transaction size and volume; and growth rates.
