Amazon offers Prime members the Littlest Pet Shop Pet Party Spectacular, model no. B3808AS0, for $12.74 with free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping costs $6.20.) That's the lowest total price we could find by $2, excluding the below mention. This toy set interfaces with the LPS Your World iPhone or Android app and includes 15 pet friends, 13 Deco Bits pieces, and two accessories.
Don't mind going to the store? Toys"R"Us has it for $12.74 via in-store pickup.