If you already have a smart phone, there are free apps available that will track and display speed, time, average speed and distance. If you want to see it while you're riding, then you need a mount for it. And to get the cadence you're interested in, you'd need a bluetooth cadence sensor (unless you've gone the extra mile to get Ant+ to a phone, which would allow you to get an Ant+ sensor instead).

If you don't have a smartphone or would have to buy a mount, you might prefer to buy a wired or wireless bike computer and get all the features you are asking for for one low, low price. I've had a few Cateye models over the years and always been satisfied.

Mainly, I wanted to point out the smartphone option, especially if you don't want to see the data while you're riding. Otherwise, I'll leave it to others to suggest their favorites and why they prefer wireless (appearance, ease of installation, portability) or wired (reliability ...).