Do a search on eBay. The aftermarket grilles don't have the same level of fit-and-finish as the OEM, but they're still quite acceptable. I just got one, and the only differences (aside from the lack of a Ram head--there's a place for one from the dealer, though) are it's all one piece, even the honeycomb, and the honeycomb is a bit thicker.
Still, I'm happy with mine. I believe a new OEM grille from the dealer is over $300. Local junkyard wanted $190! Ebay has them from $40 to $80, many you can buy immediately instead of actually bidding, and shipping is ~20. Mine ended up costing me about $70 once I'd gotten it installed.
--Ty