Existing T-Mobile USA customers will have to pay up to $380 to get the Google Nexus One, according to pricing listed on Google’s Web site. New customers can get the device for $180 with a two-year, $80 per month contract.

Current T-Mobile customers adding data plans will be able to get the highly anticipated device for $280 with a two-year contract, while current customers merely upgrading existing data plans will have to pay $380 for the device, again with a two-year contract.

The Nexus One can also be bought without a contract for $530.

A T-Mobile spokesman could not immediately confirm the pricing for existing customers, but said that “… standard eligibility requirements apply for upgrade pricing – Nexus One is not unique in that respect. We’re working with Google to fully ensure its online store accurately reflects customer eligibility requirements.”