I guess just 'street seller' is how people would describe them in the UK. Or 'street vendor'. https://en.wikipedia.org/wiki/Hawker_(trade)#Europe This seems to be what you're looking for, although I've never heard the name 'hawker' to describe them. 'Peddler' is another word that I've heard used for them.

Street vendor is the best word.

Hawker and peddler are used sometimes, but street-seller in probably more common these days. Street-seller is probably the most neutral. Hawkers and peddlers may be stationary, or may travel. When I was a child people would sometimes walk up the street hawking their wares. (selling their goods/things). French onion sellers were a common sight, peddling their wares from their bicycles. Sadly, they don't do it nowadays. I miss them. So, for people selling from a fixed position, street seller, or street vendor, is probably best. I think.

Vendor

How do you call? HEY YOU! :D and loudly. What do you call? Street vendor - check google 'hawker synonym' or thesaurus.com Street vendor