Here are the sources and some learnings!
IKEA Ribba frames starting at $4.99.
I used the white in three different sizes: 8¾ x 11", 11¾ x 15¾" and 15¾ x 19¾". I wish I had gotten at least one of the 19¾ x 27¾" (even though they are quite large) because it fits the large paper that the girls paint on in school. Don't get the 8¾ x 11" unless you are ok with a little extra work to add a wall-mount bracket on back (it just has stand on back). Be very careful with the tabs that hold the back in place as they bend and break off easily (we lost about 1/2 of them). Glass is fragile so just be careful when trying to mount the hanging wire on back (I crushed two pieces and had to replace).
Make sure to look at the size measurements for proportion and weight to make sure it won't be too heavy to hang on wall.
Make sure to ask if there is anything on back. I didn't and this has a 1/4" prongs that stick out. Our solution was to hang it on a nail and secured it with another closer to the bottom right so it didn't sway (it does stick out slightly from wall).
Diaramas $22 for DIY kit from Moomah.
The sand and contents kept shifting around so we had gorilla glued the contents to the bottom of the box. I love these on the wall because this was such a fun project to do with the girls on a day in NYC. They add dimension as well as remind of us of our fun outing!