what is the best source of funding for a solo founder ?
The best source of funding is your own pocket and the customers you generate. Remember that 90% of entrepreneurs will never get an outside dime from investors. Plan to build your business in a way that makes it possible with no outside funding. Think about "how would I create this business if it had to be self-supporting." When you don't need money is typically when you're able to raise money. People who MUST have outside money more often than not don't get it. And, when it's your own money, you are far more motivate to protect it and use it wisely.