Looking at the "sold" auctions on eBay, Sweetie Swirl on her own is pretty sought after ($18 to $30). A loose complete version of this playset sold for $55 and a MIB one sold for $130 (!!!).
They were both BINs, which is what I would recommend if selling the set; auctions are just too risky on eBay these days because you never know how visible they are going to make your auction to buyers.