I made my first real money selling door to door... but that was in Switzerland and later in Eastern Germany when the walls started crumbling.
When I lived in Ecuador in '93-'95, I first only observed the "criolio" style of peddling brooms, fruits and vegetables. But all of a sudden, well dressed lads and young ladies appeared peddling all sorts of new services... cell phones where coming up, so did Internet service and on the other hand all sorts of BS-items and "services"... all "direct sales". Well, from what I observed and what we heard some of these "sales"-people where making, many did a killing.
Latinos like to chat... that's the door in. Then, they can be taken easily on the spot if the sales pitch is tuned to their aspirations.
Signature sales with a small deposit, of which usually all or at least half was the "sales people's" commissions. Later the "officiales de cuenta" would show up and try to milk the deal as long as possible.
At the same time "visitadora medica" quickly became the most desirable "job". Some "chicas" quickly went from making USD 200.oo a month at a bank to a grand or more! It got so crazy, people started to peddle paid courses to become a "visitadora medica" and did, for a while, a killing to.
Yesterday, after for several weeks having been unsuccessful finding a new rental house in Puerto Plata going down the "traditional" route of working with local agents, I went around and distributed fliers door to door in neighborhoods I am interested in. WHILST doing so I already got people calling me and one showing on the spot. And all that after placing only 40 fliers in 2 hours. Would I be an agent, I'd have 4 new listings in 2 hours.
The great part is that people hand information around and try to help you too.
I don't know what the OP has in mind exactly, but, while I have not yet seen much of any going on here yet, except for the "visitadores medicos" (yes, here they are mostly males)... I am confident that for a person which has a good perception of how people are and operate around here, there is potential.
Still, all this does not answer the OP's question about the legality or limitations on soliciting.
... J-D.