Quote armchairecon:

It looks like the height of the faucet is factor but what else? Is it the visual things like finish or or is there some sort of internal quality to the faucets that creates the price difference?

the quality of the material, craftmanship and the quality of the internal parts for an example brass parts cost more but will last much longer then plastic parts.

also, a single handle faucet is usually more expensive than one with a hot and cold, due to the mixing valve on the inside. i personally prefer the single faucet in the kitchen, but double in the bath.

It also has to do with the designer. Just like buying high end clothes etc.