I've used Upwork and found the people I have worked with extremely effective.  It is extremely important to be very clear about what you want the person to actually do.

I have always had good work because I have taken the time to choose carefully based on a match between what they can do and what I need

I've used UpWork and Fiverr several times to find web developers and designers. I found these sites to be excellent in terms of finding people for the job. Like Ingrid, I also took my time when reviewing proposals and made sure that my instructions were as clear and objective as possible. I do find that these sites offer great value for money as long as you choose someone well-matched for the job description.