Need suggestions on a reliable

The Spark and Yaris are tiny and generally regarded as not that safe. Not sure where you're commuting but if there isn't a lot of city driving, not sure the size tradeoff is worth it.

Other than that, there are quite a few good options out there for simple, reliable commuting. How much do you like to drive? Is handling, power, important to you?

The Ford Focus will lean to the sporty side, while being fairly refined and comfortable. Some don't agree with the (in my opinion) super-awkward center console and poor built-in computer system.
The Mazda3, another reliable option, will also be sporty. It'll focus less on gadgets and more on the ride and drive. Arguably more reliable.
The Kia Rio is also going to be reliable, with a middle-ground between handling and comfort.
The Honda Civic is somewhat of a benchmark. It's fairly 'boring' but will get you from a to b every time, all the time.
The Toyota Corolla is like the Honda, with some more interior gadgetry and even less of a driving experience.

I'd recommend staying away from 4-year-old GM cars right now. :p

My recommendation is to drive 'em, see how you like them. Like I said, plenty of options, and it will mostly come down to personal preference.

The automatic transmission is a potential trouble spot in the Focus. Ideally, you'd learn to drive a manual and buy a Focus with a stick.

If you can find a Mazda3 with the SKYACTIV engine in your price range, that would be a very good way to go. Main thing I don't like about them is the interior and exterior appearance, but this is subjective.

A Yaris would be reliable, but the only one I otherwise find even somewhat appealing is the SE hatch with a stick. With a four-speed automatic it'll feel weak. A Kia Rio or Hyundai Accent drives better.

You might be able to find a 2013 Hyundai Elantra GT in your price range. This would be better than a Rio or Accent.

The Spark I'd only buy for occasional city driving. Otherwise, the next-up Sonic is a much better car--and still not one I'd recommend without the 1.4T engine, which likely puts it out of your price range.