Need Help Choosing Promotion Approach

I'm about to self-publish my first fantasy novel next month and I'm completely overwhelmed by the book marketing services available. I've saved about $800 for marketing, but I have no idea how to allocate it effectively. Should I focus on social media advertising? Hire someone to secure book reviews? Pay for email newsletter promotions?

I've looked into a few book marketing services, but the prices range wildly, and I can't tell which ones actually deliver results. One company wanted $500 just to set up some Amazon ads, which seems steep to me, but maybe that's standard?

I'm especially interested in hearing from those who've used professional book marketing services with a similar budget. What worked for you? What was a waste of money? Are there specific and expert book marketing services that specialize in fantasy that you'd recommend?

My goal is to get at least 50 sales in the first month and hopefully some momentum. I have a small newsletter (about 200 subscribers) and a modest social media following. Any insights would be tremendously appreciated as I'm starting to panic a bit with the launch date approaching!

Thanks in advance, FirstTimerAuthor