One afternoon in early 2014, an employee of the Manhattan co-working space Coworkrs got behind the handlebars of a large tricycle and began pedaling it through the Flatiron district. The tricycle was outfitted with a small desk; the employee seemed to be sitting at her desk while cycling around the city.

A company called Peddler Pop-Ups had designed the display and rented out the tricycle for use as a rolling advertisement. (The tricycles can also be used as pop-up stores.) Peddler Pop-Ups is one of six companies founded and operated by a 27-year-old entrepreneur named Danielle Baskin. She does not have any employees, and until this month, Ms. Baskin’s businesses had their headquarters in a 160-square-foot live-work space in the East Village.

She credits a variety of relatively new, inexpensive e-commerce platforms and services with enabling her to test new concepts and quickly start new businesses.

Ms. Baskin started her first venture, Inkwell Helmets, in her New York University dorm room in 2008, when e-commerce was much more difficult, and expensive, to break into. As an art student interested in optical illusions, she hand-painted a scene of a blue sky and white clouds on her bike helmet and varnished it to a high gloss. When she wore the helmet on bike excursions around the city, people frequently stopped her to ask where she had gotten it.