Spending $0 on marketing is a short-term optimization. Don't confuse it with ability to scale. Scaling requires sales, mktg & infra.
Ask a VC for money, they will give you advice. Ask a VC for advice, they will give you money.
Double-take "Unique transacting users in India ecommerce is less than 10 million a month." - Kalyan Krishnamurthy @ Flipkart #Iday2017
Unsolicited advice to entrepreneurs: Stop going to conferences. Waste of time for almost everyone involved.
With China closed off to many Western Internet products, India becoming their largest user base. Whatsapp, Truecaller already there.