I used some pieces from an old category kit from Lakeshore learning and was able to add a ton of pink and purple items from the Barbie collection. (I think I had 100 pairs of shoes alone.) I supplemented with plastic figurines (vehicles, occupations, farm animals) I bought with my 40% off coupon at Michaels. I raided old therapy games and activities, scoured garage sales, Goodwill and the Dollar Store for category materials. For awhile I just had three boxes filled with tiny manipulatives. We could pull them out in therapy and it was great for vocabulary, naming items, categorizing, talking about object functions, describing etc...
When I purchased my matching set of plastic boxes, I decided to organize the categories into three levels based on the materials on FreeLanguagestuff.com.
Five pounds of Barbie materials and 15 years of odds and ends is a LOT more than you think. So I also ended up with an Object Functions Box with suggested levels from Freelanguagestuff.com.
But that wasn't all. I still had enough to create a 2 syllable and a 3 syllable bin.