Are you talking about one of these? (pictures below). This is my Tatum in her pink one and Stedman also has one identical to it that is blue. I got both of them at Bed Bath & Beyond for $20 each, course, I had a $5 off coupon at the time
lol
That was, oh gosh, about a year and a half ago though
My mom went in there looking for one for her little girl Kenzi and they didn't have them anymore
I would try looking online, even eBay would have them I'm sure. I know that Wal-Mart carries them in the childrens section, but all the ones that I have seen have characters on them (Dora, Elmo, etc.) Not sure if you want that.