I am trying to remember the word to describe a person trying to sell stuff persistently. I can't seem to figure it out.
It can be a verb, noun or adjective. Anything around "Selling stuff persistently".
Pushy or pushful
marked by aggressive ambition and energy and initiative; a pushful insurance agent
A pushy door-to door salesman OR a pushy salesman
This is one of the most common misconceptions about business today. The reason that people think of salespeople as being pushy and aggressive is because for the last 60 years, they have been pushy and aggressive. Most sales people today still are.
making continual and persistent demands
continuing to believe something or to do something in a very determined way [= tenacious]
This is more formal, has a more positive spin, but really means the same as insistent, and persistent.