The only selling that I do online, I do through Etsy, an e-commerce portal through which small craftspeople, artisans and artists - and groups thereof - can sell & buy a wide spectrum of handmade & vintage work, as well as supplies. More information on Etsy can be found on their website (www.etsy.com).
My Etsy store can be found here, my shop name being "Grungepapers" if you need to do a search for it from the Etsy main page.
Generally, if I have made enough of a specific item - a printed poetry broadside, a kind of handmade paper, etc - that I can meet my own needs and still have leftover stock, I will list the item on Etsy.
If you are in the Ottawa area - Ottawa, Ontario, Canada, that is - The Grunge Papers usually has a table at the Ottawa small press book fair. The Ottawa small press book fair happens twice a year - in the spring and in the fall - with information about the fair usually to be found on the (Canadian) Small Press Book Fairs blog located here. The fair is organized and run by rob mclennan, so information about it can also usually be found on his blog here.
The Grunge Papers sometimes takes part in local (Ottawa area) arts & crafts fairs and sales. The only one of these that I seem to take part in consistently is the Sandy Hill "One and Only" art + craft sale, the blog for which can be found here.
Unfortunately, I do not solicit and will not usually accept printing or papermaking jobs. What I do under the auspices of The Grunge Papers I ultimately do as a hobby - or possibly as a personal obsession - and so I'm generally only interested in printing and making things that are of a particular interest to me. In publishing terms, The Grunge Papers is a private press, printing only work that I myself find interesting.