The only place I have heard of is Etsy. And everyone I have known that has put their stuff there for sale, has had no bites. I have bought one thing from Etsy. A neck warmer. One that goes into the microwave oven.
There is an eclectic shop in Everett and they will buy a limited amount of your handmade jewelry and other items. Also along Newbury Street in Boston, which is the Rodeo Drive of Boston, has shops that buy handmade stuff also. In Malden, they have a senior shop. Most of their stuff is baby stuff you can buy as gifts for the newborn. It is beautiful work. Everett and Malden are both blue collar cities and these stores made it through the recession. Most of the shops on Newbury Street have closed.
I would suggest she try to find a small shop in her area and see if they would be willing to put her stuff on display for a commission. And she has to remember, the store knows its customers and what they are willing to pay.
Also with the warm weather coming, she might consider buying a table at an outdoor flea market on the weekend. Depending on the size she wants to rent, it can cost anywhere from $10 and up. One table should be enough to start. What isn't displayed on the table, can be stored underneath and brought up to replace what is sold on the table. Just make sure she keeps it clean and covered until she puts it on the table. Don't price it too high. And bring something to take her out of the shade. It helps if she has someone with her so she can take bathroom breaks. Also try to get a spot up or near the front. Very few of the visitors make it to the end. Look in your local newspapers for flea markets in your area.
Hope this information is of help. And I wish her good luck.