OC Merchants

Act 1
When selling items, it's beneficial to sell as much as possible to Sand in the Docks District of Neverwinter. However, note that he has a selling cap of 10,000 gold pieces, and his store has a finite amount of gold. So it is best to sell items that exceed his cap to other merchants.

In Act 1, almost all merchants other than Sand will buy your items for the same amount. However, Tarmas in West Harbor and Reylene in the Neverwinter Docks District will pay you slightly less. For any item that exceeeds Sand's selling cap of 10,000 gold pieces, or for any item that you want to sell after Sand's store no longer has any gold, Repko the Weaponsmith or Werth the Armorsmith in the Neverwinter Docks District are both suitable options, as are Deekin and Pap in the Neverwinter Merchant District. Jacoby and Tor in Fort Locke and Edario and Branson in Highcliff also will buy for the same gold amount as (most of) the Neverwinter merchants.

Act 2
Beware in Act 2 because Sand's store now buys items for the worst price! Whatever you do, do not sell items to the Merchant Elemental in his store. You'll get a better price for the items at any other store. Repko and Werth remain good options, as do Deekin, Pap, Jacoby, Tor, Edario and Branson.