In an ideal world I scan horde AH, scan alliance AH, i click export and i can see in a spreadsheet the difference between predefined items.

Anyone an idea what's the best way to compare prices cross faction? I personally perfer a spreadsheet (or basically any exportable format will do) rather than an ingame tool. But anything will do, cause so far i look up all the prices of the stuff i'm interested in by hand, and store them in a spreadsheet. Got bored of this tedious task.