as a single mother I want to say this touches my heart to see ya'll doing this for another single mother. I have two kiddos so I can offer some toy advice ... board games like guess who, connect four or aggravation all ages will play, puzzles are great, play dough with cookie cutters entertain for hours around my house, coloring books with crayons are great, simple card games like crazy 8s or uno are good too several can play at once. construciton paper, drawing supplies, glue, glitter and scissors for paper crafts. sun catchers and paintable simple shapes in the craft supply area are good too.
fun toothbrushes, yoyos and slinkies make great stocking stuffer items.
hope this helps ...