Which merchant has the most $ ?

ex. Jensine has only 600 to spend per item

Go to the Merchants Inn. There will be a Dark Elf male there. He will have 2000 to spend.

Im not sure, but you might need Battlehorn Castle DLC to see him. Check anyway.

Merchant cash amount isn't the only thing to consider. For instance, Thoronir only has 800, but he's an Apprentice level at Mercantile, so you'll get good deals with him on the lower-priced stuff. Most of the merchants with 1200 are at least Journeyman level, except for Varel Morvayn in Anvil, who is Apprentice, but only buys weapons, armor, and miscellaneous.

Sinderion, the alchemist, only has 400 gold, but he'll give you the best prices for your ingredients and/or potions, because he's only Novice level at mercantile.

If you don't have any DLC's or mods, then Fathis Ules, the top fence for the TG will go to 1500, but he's not exactly generous. Being a Master in Mercantile, he'll swindle you penniless.

so why are their items

ex. 22100 Mennomarco's Robe

how do you get 22100 on top items ?

You don't. The high prices are just a way of showing relative value.

The most you'll get for that in Vanilla, unless you're Thieves Guild, is 1200. And since it's clothing, your best bet is probably Palonirya in the IC.

If you've reached Expert in mercantile, you can invest in a shop, and it will have 500 more gold. And when you're a Master, you get the 500 extra everywhere, plus you get full price (up to the merchant limit.)

By the way, the Dunmer I mentioned. He buys anything.

He is only available with that DLC, though.

Once you're at a level to get these items, money is not normally a concern. They can't be bought, only found in random loot or on specific boss NPC's, so the "price" is only a potential selling price.

My opinion on why they set prices like this is so that you don't want to sell them. The developers wanted you to keep them, even if it was only to display in your home, so they set a high price you can't get from a merchant to persuade you not to just sell them. They could have labelled them "priceless" but didn't.

That DLC is not that expensive, and it's a pretty cool place to live if you can afford it. I use that Dark Elf as my primary merchant unless I need my armor repaired of my weapon recharged.

Yes you also has the chance of finding real expensive items at low level, Goblin totem staffs is fixed and giving the character to much money early will unbalance things.
If Morrowind and Fallout 3 merchants has limited total money so they could only give you 800, then you had to wait three days for them to get more.

Think of merchants in Cyrodiil as pawn brokers. If you take your grandmother's heirloom diamond ring to a pawnbroker he's going to try to give you a fraction of what it's worth. If he only has $200 on him that day, that's all your going to get for that ring, unless you come back when he has more money or you go to another pawn broker.

Tamriel's economy is not the modern capitalist economy you are familiar with. Its economy is a barter economy and, as such, there are no fixed prices. Each transaction is a feudal exchange between private individuals.

Why? Because that is the price a merchant would work with if he was trying to SELL you such an item. If you sell that robe to Jensine, she'll give you 600 for it. If you immediatelly try to buy it back, she'll happily charge you way over 22100 for it.

Your best loot to grab are things that sell for an amount that doesn't stress the merchants' max, but weighs very little (scrolls, rings, amulets, arrows, potions).

Your best barganing is to use the link below to find a merchant who has decent cash and not so great mercantile skills. Then charm his dispo up to 100 and haggle.

http://www.uesp.net/wiki/Oblivion:Merchants#Merchants

The merchant with the most cash is Fathis Ules although he's a master in merchantile so expect a tough time when trying to haggle him. The best merchant to sell to is either Jensine who you can sell items up to 600 gold and you can haggle with no problems. The Khajitt in the Dark Brotherhood who you can sell items up to 400 gold however he is extremely easy to haggle up to 80 % or more thats great to do if your selling a whole bunch of Welkynd Stones. Lastly Cutter in the Shivering Isles you can sell up to 1200 gold and you can haggle her eventually getting her up to 80 % although you can't invest in Cutters shop.