In addition to defining "affordable" ou also need to give us a picture of what you mean by "sports-watch." Me, I would point you to a G-Shock, my preference is solar atomic. As such,
I am going to point at this one.
If you give a clearer picture of what you are thinking of then we can probably do better. That being said, there are
forums that are much more watch centric, and you will probably get better advice there.
/*edited to add*/
Okay, I see you are looking for a GPS watch. That narrows it down a lot. I decided against the watch for data tracking. However, that may change.
The thing is that I always have the phone with me somewhere. I have been considering adding a
heart rate tracking ring.
For a watch, as mentioned by others, the Apple watch is well regarded, I notice that many of my co-workers wear them. Other than that, as mentioned below, look at the fit-bit offerings. Catagory leaders get there for several reasons, and Fit-bit is so much a category leader that the name is nearly generic.