In January this year I'd have recommended the XOSS G+ for only $50 or less. However the coronavirus pandemic seems to have hindered XOSS to some extent. The devices are still readily available on Amazon. But XOSS hasn't been replying to user questions on their Facebook page since late February, and the app hasn't been updated since then. Mine still works fine, with only a single glitch since January and 1,000 miles of rides in the 20-50 mile range, about 3-4 times a week. But it's an iffy buy right now.

If your budget can stretch to $100 or less, check out the Bryton Rider 10 and 15, Lezyne Macro Easy GPS and Mini, and maybe some discontinued and/or refurbished Garmin and Wahoo computers.

Or, if you don't need to see any data displayed on the handlebar/stem during a ride, a smartphone will work just fine for most data. Just one or two simple Earth induction sensors from many makers for around $25 each. These are usually dual-function for speed or cadence, switchable by removing and re-inserting the battery and watching for the LED colors to change. No magnets needed. These are Bluetooth or ANT+, so they're compatible with almost any smartphone.

If I bought only one Earth induction sensor, I'd set it to cadence. The phone and app can handle speed remarkably accurately via GPS. And a heart rate monitor like the Wahoo Tickr.

But running the phone on the handlebar/stem as a bike computer, display running constantly, will drastically reduce the battery runtime. And most phones are heavy and bulky enough to detract from handling a bit (I found it hard to bunny-hop with the phone on the handlebar, while the XOSS G+ weighs almost nothing and doesn't affect the feel).

So when I use my phone as a bike computer, I set it before a ride, then turn off the display, stick it in my pocket and usually don't look at it again until the ride is finished.

The main thing I like a visible computer for is to check my heart rate for structured training, and keep track of time. I also vary my cadence depending on my goal for that ride. I don't pay much attention to speed.