T-Mobile has an offer on its Nexus 5 which is a discount of $24, reducing it to $372. It includes T-Mobile service which does not require a contract.
The Nexus 5 of the same configuration (16GB) costs $349 on the Play Store, still being $23 cheaper than the T-Mobile’s discounted version. However, should you purchase it from the carrier, they will allow you to add a T-Mobile plan and pay the cost in installments. This will cost you a bit more over time, but help you in the short run.
To claim this offer you need to enter the promotional code ‘NEXUS5PROMO’ while checking out on the T Mobile site, as explained on their official tweet. Do note that this offer is only valid for Web orders and not from retail store purchases of the Nexus 5.