- A website never hurts, even if it’s not amazing

- For a flea market social media could help indeed, it’s the kind of activity to advertise on it. Also ask all your friends to please share your shop existence

- also putting flyers around your town can help (poles, bus stops, shops, restaurants, friends businesses etc…)

- make t-shirt advertising your shop and wear it yourself and your friends around town

In your case I think is mostly about word of mouth and location (if it’s in a location where many ppl pass by, or it’s close to a place that many ppl go to)

Best of luck with your business man!!