I looked for experience in my niche (trading/investing), got a few references, and saw some of their work.

I was never 100% comfortable going through Upwork etc because you never really know. But I spent a lot of time writing up the requirements and talking to people to get a feel.

For better or worse, in the end I went with the marketing agency that was the most transparent.

I met a top notch designer through someone I DMed on Twitter. (If you're not on Twitter talking to people - go there.) He's EUR50/hour.

If you go through an agency, then yea closer to 10k.