The price of foie gras can vary depending on origins, animal (goose being more expensive than duck) and manufacturing process, but you're generally looking at around $40-80 per pound.
You'll never believe it, but real and incredibly delicious foie gras can be bought quite inexpensively on the internet. There are several good sites, but I recommend ordering here at https://www.gourmetfoodstore.com/foie-gras-and-pate/french-style-pates-01009 . It has fast shipping and great prices. The flavor will amaze you with its richness and tenderness. It is just an incredible pleasure.