Checking my math

[Saxavarius]

An earring of Prestidigitation usable 3 times a day would cost:
.5 x 1 x 2000 x 0.6 x 2=1200

Is this correct or did i mess up somewhere?

[Kethrian]

It should be command word activated, making the base 1800 instead of 2000.  You also don't need that final x2.  This changes the final price to 540gp.  For 900gp, it could be used at will.

Edit: was that last x2 for unslotted?  Then it applies.  An earring can take the head slot, though, which is what I initially assumed.  If you stack it onto another head slot magic item it would only be x1.5.

[sirpercival]

It should be command word activated, making the base 1800 instead of 2000.  You also don't need that final x2.  This changes the final price to 540gp.  For 900gp, it could be used at will.

x2 for slotless.  Earring is not a slot.