What are budget prices?

Budget prices are the price at which your unsold bushels are set at (after you click the budget price toggle).

As a reminder, your average cash price is the average of your sold/contracted bushels and your unsold bushels.  Your unsold bushels are "marked" at the current futures price for that crop year less the basis you have in your Settings tab.  If it's a crop that doesn't have a futures market, the unsold bushels are automatically "marked" to the cash price in your Settings tab.