I often get called by companies when their first version of a product isn't exploding and they think marketing will fix it. But nothing spreads the word about a bad product better than good marketing. I will actively refuse/postpone clients who aren't ready for us yet, because marketing cannot fix a product/market fit problem. ( We can still sometimes help--you might need your google analytics installs retooled to get the right data, or to get the most out of the reports, some insights about what is and what is not working, or to create a plan for testing.)

So, my advice to you is to build a product that doesn't require you to spend money on marketing. Understand and love your customers so that you can anticipate their needs. Stay focused on it -iterating, evolving, measuring, growing-until you have very low churn rates. Low churn/recurring revenue will be what allows you to spend money on marketing and possibly raise investment. If you spend money finding customers who don't stay, you're only renting them, not acquiring them.