A direct quote from the page... "Store- In this store, you will find everything you need for your horse. If you no longer use certain items, you can also resell them back to the store."
In the store, you will find pretty much everything. There are the food, equipment, and companion tabs. If you want to know what's in each, it's pretty simple. In the food you will find apples, turnips, and all of the mashes (aside from Health, which the equestrian center provides.) In the equipment you will find... wait for it... equipment. Western, English, and horseshoes. In the companion tabs you will find all of the companions available for direct purchase. There are others, but these can be found during promotions, through opening HOPs (Horns of Plentys), and possibly if somebody is selling them through the trade. Certain items can be sold back- but you only get half of the price which is currently displayed. You can also view your total inventory as a breeder, including BM (Black Market) items. Last but not least, you can access the item trade from this page.
In the store, you will find pretty much everything. There are the food, equipment, and companion tabs. If you want to know what's in each, it's pretty simple. In the food you will find apples, turnips, and all of the mashes (aside from Health, which the equestrian center provides.) In the equipment you will find... wait for it... equipment. Western, English, and horseshoes. In the companion tabs you will find all of the companions available for direct purchase. There are others, but these can be found during promotions, through opening HOPs (Horns of Plentys), and possibly if somebody is selling them through the trade. Certain items can be sold back- but you only get half of the price which is currently displayed. You can also view your total inventory as a breeder, including BM (Black Market) items. Last but not least, you can access the item trade from this page.