Budget Activity trackers

I’m trying to up my game and accountability so I have been looking into Activity trackers. My exercise regimen is fairly unusual as most of my exercise is done via farm work. As I create exercises I research and find references but sometimes there no easy equivalent to say digging a post hole requiring the use of a 30 pound breaker bar and it taking many minutes if effort. So….are there any activity trackers that are reasonably priced and that would provide me with more accuracy regarding calories burned?