I can see the desire to get such a gadget. I have some gadgets myself. When I first started running a lot about 10 years ago, I wished for, and got, a Garmin. It was a few hundred dollars. That thing was glorious, though - helped me a lot to track distance, speed, splits, and it was fun to go back and see where I'd been on a map.
Software was glitchy though, then I got injured, and it gathered dust.
Fast forward many years through injury and childbirth and hey, now I'm running again. Several friends have Fitbits and do challenges. My husband started checking reviews on various types of fitness trackers. I then followed his links and realized - pretty much every one dies at about 1 year. So even though at this point, they are only $100 or so, I am not willing to pay $100 for something that will need to be replaced in a year (some last longer, a lot die earlier).
So. I use the app on my phone. There are many. I have friends who enjoy Strava and runkeeper. I use Map My Run/ Map My Walk/ Map My Ride. They are all the same. I have four friends on there, only one that's active. We do a challenge or two every year, but I cannot beat him. Even when I was training for an uphill half marathon...apparently a 225 lb man walking 6 miles burns more calories than a 135 lb woman running 11 miles up hill. Who knew?
I agree that you need to get into the habit first. Use what you have. I do LOVE being able to look up my old runs, paces, etc on Map My Run. My neighbor with the Fitbit? She started getting obsessed with the numbers and had to take it off.
For the record, last year with half marathon training I dug out that Garmin again. It's a beast! I mean, it's huge. People make fun of it. I no longer have the software. I charge it up and use it as a pacer/ timer.