1) SEO (optimizing content, building DA and writing new content) 2) Social media (creating engaging content and posts on social channels.
For a variety of reasons, I'm going to prioritize organic SEO or social media over paid ads on Facebook or google.
With this very limited context, where would you put your money?
Why?
Simply because in the "long term" all the competitors of the brands we helped outperformed our clients.
But there is a caveat to this...
Before you invest in SEO, you need to know which content will perform.
So, before investing in SEO, I would:
1. Write 10 different articles that cover topics that your client cares about. These can be short, the goal is not SEO. However, they must be good and have value.
2. Take $2,000 of your 50k and mark it as your "test budget"
3. Run FB ads to these articles as content ads. Make it clear in the ad which problem each article. Put all 10 ads as $10/day. You will run each article for 5 days. Go live. This is a 500$ test.
4. Write another 10 articles that cover a different 10 problems. Repeat the above. $500 test.
5. Repeat 2 more rounds. $500 each.
6. Now you have an enormous amount of data that tells you what your audience cares about. Start SEO based on this data.
7. 3 years from now, you will be well beyond your competition, unless they started SEO 10 years ago... haha :D
The point here is to use data to fuel your SEO strategy. While im not an SEO expert, I can tell you that most people spend time writing about things people do not care about. You also want to do keyword research to optimise the topics people care about (but this is step 3).