I ran a search on the forum for "creeper", only 2 pages worth of results came up, and none of the thread seem to be relevant to what I want. I am looking for mods that'll tone down these 2 merchants so that I can't easily be rich by exploiting them.

And before anyone says "just don't trade with them"... no. I don't want them totally removed from the game, I just want them to not be a cheap source of gold. Perhaps if the creeper doesn't buy everything at base value, or maybe a have a lower amount of gold supply... perhaps maybe even a long-ass, hard quest that has to be completed before the creeper becomes available for barter...

Using http://search.yacoby.net/search?general=creeper&game=3&act=Search&page=1 you can see there are many, many Creeper mods. But they all seem to give to him more money.

But you can easily and quickly make this mod yourself.
Just open the Creeper's AI window, and go to the Services tab. Lower the amount under Barter Gold.
Save, and you're done.

You cannot make Creeper buy items for anything less than base value, because he's a Creature and therefore doesn't have Disposition that affects bartering.

They can't really be toned down because the problem is that you get full price because they're creatures rather than NPCs. You could replace them with NPCs that are custom mudcrab/scamp races, but then you're spending too much time on something this stupid.

You'll have to settle for lowering the gold available. Creatures don't have a mercantile skill, or any real skills for that matter, so you'll only ever get the base value for items. A quest is certainly possible as well.

Okay, guess I'll have to learn how to use the construction set then. Have never made any mods before...

Thanks for all of your suggestions, guys.

Be careful. Once you start, you may never actually play again! For this, just open up the CS, load Morrowind.esm with this mod, but do not set it to active, otherwise you will modify it. http://wryemusings.com/#NotesandUtils.

Find the creatures tab. To make it easier to find Creeper, click "Name" to sort by name. Once selected, click "AI", then "Services", and you can modify the barter gold and, if you wish, what items are available for barter. Repeat with Mudcrab, save, and you are set.