Example: Market size 150,000 or less on a yearly subscription model ($60 per year) for a total of $9 million annual revenue at most. Costs estimated to be less than 500,000 annually.
1. If you are growing by 2,000 users or $1,000 per month.
2. If you have a very high tech idea and are a very good marketer, such as Theranos, Magic Leap, Tesla.
But you should normally start with Angel Funding. VCs aren't suitable for pre-traction startups for a multitude of reasons.