The fastest and easiest way to...

[pesgores]

...inventorise your MOC pieces and import it to any LEGO selling website (Bricklink) to see who has got all the pieces we need, in the quantity we want, in the color we want, all in the same shop?

I know the old way, piece-to-piece, but is there an easier and afstest way of doing this?

Thanks in advance

[MarcusV3]

It'd be great if someone new this. I would like to know how as well

[puddleglum]

There is a feature on BrickLink called a "Wanted List":

http://www.bricklink.com/wantedAdd.asp

You can add parts in specific colors and quantities to the list. Then, you can see which shops have the most parts you need by clicking the "By Shop" tab and sorting by Lots (Unique). (If it's a very large list, you probably won't find one shop with every single part you need)