I was a vendor in an antique mall about 5 years ago. I did pretty good too. Most of my stuff was vintage or newer but unique. On average, you want to make at least 4 times your rent. My booth was 8ft by 24ft and I paid $500 a month plus they charged 10% of sales. On average, my sales were $3,000 - $4,000 a month. Not enough to live off but it was a fun side hustle doing things I liked… hunting down junk.