How do I sell magic items? I have a very valuable Staff but can't sell it to the usual outlets

[Tyro]

Is there a magician somewhere who would buy it? Thanks

[Mormacil]

Staffs can be bought by court wizards and maybe general stores, if it can't be traded check if you can drop it and it isn't a quest item.

[Sanjuro357]

There is/was a bug where the general goods store in Riverwood had 10,000 gold, but I think you had to invest in the store first. This may have been removed in the most recent patch, but I'm not sure. Another thing you can do is buy everything you want from a store before you sell them an expensive item. There are also skill teachers at the college in Winterhold, who can help you level up various magical skills, who are also merchents. Pay them to learn those skills, then sell your items to them.

[Roscaria]

Most stores will only pay you a fraction of the supposed value of your items so check with the College of Winterhold mages. They usually have a reasonable cash supply.

[TTPowell]

Richard has the right idea, but mine is a bit different. I invest in shops to max then buy a crap load of stuff from them then sell. I usually buy all the ore, ingot, and arrows from the blacksmiths and then sell my enchanted items and what have you. At the court wizards like Moracil says buy all the soul gems and everything useful then sell. Spend some to make some. :)

[Fury]

or use the command line :) I use the no clipping mainly and thats it though.

[Roscaria]

Or you can get one of the merchant mods available in the workshop.