Dear BikeForums.net community,

I need to purchase a single speed commuter bike on a budget (preferably in the 200-400 range) and would really appreciate your input.

I will use it to commute approximately 6 miles total 5 days a week. This is in NYC so there aren't really any hills.

I have a long torso and a slipped disk in my lower back and would therefore prefer an upright ride. I would also prefer something relatively light since I plan to carry it up two flights when I arrive at work.

Here are some of the options that I've looked into:
Amazon.com: Critical Cycles Fixed Gear Single Speed Fixie Urban Road Bike: Sports & Outdoors
Schwinn City Single Bike - Dig In HUGE SAVINGS While Items Last

The bikeshop near me has a single speed Torker for only $350.

Thanks in advance for your input! There's a lot to learn and I really appreciate you sharing your expertise.