How do I view beginning inventory balance, ending inventory balance, and purchases during the year?

You'll need to run an "Inventory Report". When you click "Reselling Reports", you can select the "Inventory Report". Once purchase dates and purchase prices are updated, this report will provide a summary of beginning inventory, purchases during the year, and ending inventory -- there's a download icon next to each so you can download the detail.

There's also a line for "Cost of Goods Sold", which you can download a detail for as well. If your "Beginning Inventory Balance" + "Inventory Purchases During the Year" - "Ending Inventory Balance" doesn't equal your "Cost of Goods Sold", check your sales for items with a purchase date after the sale date.