I tried to find more about the ponies since I am no g3 expert. It seems Pinkie isn't sold recently on ebay but Rarity was sold 80USD (she was in her bag, unopened) and she only got one bid so there wasn't much "fighting" over her. If your ponies are of the bag, their value is less propably but I think they are pretty rare that those who collect g3 might be very interested on the ponies. Exact value I can't give you (sorry ) since I am not that familiar with g3 ponies.