The HTC One M8 has been on the market for three months roughly and you would not expect to see any discounts on the handset at this point in time. However it seems that one seller on eBay has broken the rules as they are selling a factory unlocked M8 for $549.99, which means savings of $150. It also comes with free shipping in the US and you can get it shipped to many other countries.
This is a brand new phone and isn’t locked to a carrier. So you should be able to put in any GSM-LTE SIM card and use it. The device is available in metallic silver and grey, however the gold is said to be out of stock.
The majority of people buying this will not have to pay taxes as the seller is shipping the device from Houston.