re: "I'm trying to determine the cost of hiring a freelancer to help setup the video uploads in my Jomsocial community (in my Joomla website)."
All you need to do is go to the main Upwork site:
...and post a brief description of what you want done, as far as setting up video uploads in your Jomsocial community, on your Joomla website.
If you have a clear idea about what you need done, which you can describe as very specific steps, then you may post a fixed-price contract with a $5.00 "budget", and state that the budget is placeholder. Ask freelancers to state how much they would charge for such work.
Otherwise, post an hourly contract job and when you talk to respondents, ask them to estimate how much time (which translates to cost) it will take to do the work.
For best results, hire more than one freelancer and continue only working with those who provide you with the best value.