I am developing my pitch deck for a local services double side marketplace and I am not sure which are the best strategies (and cheap).
There are so many answers to this question, but really it depends on what the market is. The first question to ask yourself is, where do your users (both kinds of profile) already hang out? Where do they live online?
Maybe there are certain social networks, certain forums, certain publications. Go there first.
Even more critically, the best way to growth hack for something like this is to take an experimental mindset. Choose 3 or 4 different user acquisition techniques and run a small, time-bound test to see which one performs best. Then, ask yourself why this method outperformed the others. Take that knowledge and choose a few more methods and test them. Rinse and repeat.
It will be high effort at first, but you'll learn fast. It's always better to just start and get your hands dirty than spend much time trying to find the 'best' strategies.