This is not a lot of money, but it is enough to spend well. How would you best spend this money on marketing?
Maybe look for some micro influencers from your niche
Split into 3, 100$ experiments of paid click champaigns
(Make sure you have a system for early user capture first)
I would probably look into signing up to a tool that would help me do a better job at growing.
Like Buffer for social updates.
Or a tool for SEO.
Or perhaps a course or books to teach me marketing skills for life.