Help, which shop is best to sell items?, Who can afford my expensive items? Options

[TomTom]

I've been playing Oblivion and i am wondering what the best place is to sell my expensive items. I hope someone can help me with that.

Untill now I sell my loot to Thoronir in Market District because he has the maximum of 800 gold to give me for a item. I have items which are worth 5000 gold which i don't want to sell for 800.

Is there a shop or person who has a bigger purse then 800 gold? Or is there a way i can raise this number for Thoronir so he can give me more money for my items.

My disposition is already maxed, at 100% and i now haggle around 65%. So that isnt the problem.

I've looked in this forum and read something about investing in shops. Maybe i dont understand it right because it didnt work for me. I bought at Thoronir a item for example worth 3000 gold hoping he had more money to spend. After that he still has a maximum of 800 to spend to me.

Thanks in advance for any usefull tips.