Which Outsourcing Company is the Best?

Hi, I have been looking into outsourcing flyer designs.

I tend to earn about $50 per 20 on Graphicriver, per.. month, and Creative Market and another one, should double that.



I figure that l need about 625 flyers initially

With about 415 getting into GR, (which is exclusive) and then doubling the rest on the other two sites that aren't exclusive.



So l have looked into Freelance, and let's just say that it is on my short list.

Then l tried this one,..https://www.upwork.com

This used to be Elance, but changed their Company name, l haven't looked into this one much yet, but this seems to be a good option.

Then this one,..http://www.virtualemployee.com


This seems like a good option, but having to pay $1000 up front, and some 15 day thing, to hire someone for a month seems a bit extreme,

I know that l can test and reject candidates, (and give them a test) but $1000 up front,....he might take the same flyer and change the background a few times, just to keep the pace up?

So, anyone out there used any of these, (especially the last one) or another company l haven't thought of.

Or is there another option?



PS already tried Fiverr, but they want $20 or more for one flyer with PSD and rights. And tried graphic artists there a while ago, to do flyers with pretty average results.