Location of the Creeper Merchant - Elder Scrolls: Morrowind
The Creeper Merchant is one of 2 unique merchants in Morrowind that has a very high initial amount of gold stocked and will buy all of your items at full price. As far as I am aware there are only 2 merchants in the entire game that pay full price for every item - Creeper and the Mudcrab Merchant. The Mudcrab Merchant is a bit out of the way so typically I personally use the Creeper Merchant instead.
You can find the Creeper Merchant on the 2nd floor inside of Ghorak Manor in the town of Caldera. The easiest way to reach Caldera is by talking with any Mage Guild Guide and asking them to teleport you to the town of Caldera. You'll find Ghorak Manor a tad bit east of the Mage Guild - it's a very short run and easy to find.
Much like with all other merchants in this game the Creeper restocks his gold supply every 24hrs. If you have many items you're looking to sell you can unload whatever you have on you then 'Wait' for 24hrs right next to the Creeper until he restocks. Early in the game if you get your hands on some Ebony, Glass or Daedric weapons or armor it's typically advised that you sell them to this merchant or the Mudcrab that way you can get as much gold as possible for your sales.