@Abdul Jabar weird, when I responded to your post there was only the title - "$80K Cash-What should I do?" There was no posting or info beyond that. Maybe a glitch on the BP site.
Now I see what you're asking. I don't know anything about Roofstock, but I am not so much a fan of these investing platforms trying to shortcut or "democratize" the process. I gave Peerstreet a chance and am not happy with it. Inflated property valuations, poor communication and subpar returns. I'll be closing my account once I can escape the last 2 positions (one in foreclosure, the other is REO).
If you already work 2 jobs I don't know how you could buy a business, unless you put the $80k down on an established & profitable franchise (e.g. Subway) and then you work there as your own employee/manager to save costs.
My RE thought is you look for a duplex to buy with $80k, live in one side and rent out the other. Slow and steady, buy another one in a few years and so on. Good luck to you.