I am just starting out, but have come across a couple of fairly expensive goods in the wilderness (worth 6500 and 4500). However, most of the merchants that I have encountered don't have this much gold! Where can I sell them for the most money?

Go to the Ghorak Manor in Caldera. On the 1st floor there is a Scamp called Creeper. He has 5000 gold to spend per day. Not enough to buy that thingy worth 6500 of yours, and not nearly enough to buy the most expensive stuff in the game, but you can easily circumvent this. Sell him the 6500-piece and simulaneously buy some stuff from his inventory worth 1500 gold, thus bringing the "total sold"-sum to 5000 exactly. Now wait for 24 hours for Creeper to replenish his money and sell him the stuff you bought from him for 1500 gold. That way you'll get the full worth of your hard-earned loot, although this will take a long time later on in the game when you're selling off some heavy-duty stuff.

There's also a sentient Mudcrab(!) somewhere who can buy up to, I believe, 10,000 gold per day, but he's in an inconvenient spot to get to.

yeah, mudcrab is a sucky spot. i prefer the cheaters method: take a calculator and add up the value of all the items you want to sell, write that value down. now, hit the tilde key (~) which is located above the tab key on the left side of the keyboard. this will bring up your console

in the console type:
player-> additem "gold_100" X

where X is the value of the items you want to sell. DOUBLE CHECK, there is a bug where it doesnt always give you the right amount of gold when you do this. now, go to ONE merchant (so that you dont have to hunt down items if you need them later, you know exactly where they are) and sell him everything for 0 gold, that way fair is fair, and you don't waste hours doing the repeat sale trick (which takes forever when you have 2 million dollars worth of stuff to trade).

Or simply download the plugin that gives the Creeper 100.000 per day, and you'll no longer have to deal with such petty issues.

With the exception of the mudcrab and creeper, don't expect to get full price for any item, but don't expect to pay it, either.

Its interesting to take a weapon to Balmora [since there are 5 or 6 people who'll buy it in a very small area] thats worth [say] a hundred to each of the merchants and see what they'll give you--just 'cancel' each sale till you find your best buyer.

2 things worth remembering: you train your mercantile skill with each sale/buy. Buy/sell items like arrows one at a time to train it up quickly, dosen't take as long as you'd think.

For really big ticket items, your best opportunity to sell them is going to be when you have an item professionally enchanted. Enchanters will buy anything not specifially related to alchemy. If you sell them something cheap before hand, any money you pay for an enchantment is added to their inventory, and they'll buy your pricey weapons, etc. I actually leave a few spare daedric and ebony weapons at the enchantress's place for later sale...

Oru

To elaborate on this a bit, you specifically have to haggle, i.e. buy stuff for less than the merchant's initial asking price and sell for more than he initially offers. If you just buy and sell for whatever comes up as the 'total cost' and don't use the + or - buttons to alter that, your mercantile skill will not change.

I have downloaded the "creeper"plugin from Morrowind source. Do I now just have to copy it into the data file directory? When I click data files when loading morrowind, it doesn't give me the option to add this file. It is an .rar file, whatever that means!

Thanks

The files(s) are compressed and you need a program like WinRAR or WinZip to open it.

Note about plugins: They are often ICE'd for some unknown reason. As if zip and rar weren't the most used compressing programs. You'd better go to download.com and download something that is able to unpack .ice files.

That's not enough, some of the items in the game worth more than that. a 1,000,000 creeper mode would be enough for anything.