It all depends on how big and how fast you want your pig to grow. There are many differnent things you can feed the pig as well. The higher the protein, the more you feed your pig (unlimted) your pig...
It is just under $14 per 50 lb bag or at 2% less protein you can get all breed for just under $10 per 50 lb bag. Keeping in mind that pricing may vary depending on where you are located...
If you live in the UK the food ranges from £3.00 - £12.00 depending on the food and size of the bag otherwise it is from $4 - $10. Hope this helps you.