The only $500k houses that would likely even have a chance of cash-flowing would be distressed or low-end properties in extremely expensive markets.

There's a very good chance your niece will disappear as soon as she see's you're serious.In the future, don't even rent to friends or family.

https://www.biggerpockets.com/blog/2015-01-14-rental-property-manager-how-to-chooseHave you had a chance to find any property managers in your area?

Bathrooms - Must be fully functional.Pools - Equipment must be functional and water must be clear enough to see bottom.Paint - No peeling paint (especially if date of construction is pre-1978).Floors - No bare concrete.

I feel like a house hacker has a better chance in this situation.

Is there a chance that the $100 per month could actually be -$100 a month?

Some will want cash, but you have a chance to mortgage.

@Diana T.Hi I really like the advise you have been giving people I am only 15 and I have a few jobs in the summer and I only make around $2500 so I save it up the goal is I want to buy a property eventually recently I put $3000 into Stocks now since I’m stuck In quarantine I started to try to learn more about the real estate world I wanna know what tips you can give me and is it too early in my life to start thinking about this I want to ask you because no one in my family is really into real estate it’s just me and this is the path I want to take so I just wanna know what you can tell me I understand you’re really busy so whenever you have a chance Thank you so much

You've got a chance to sell. 

It's barely science anyway, since it depends almost completely on the whims, actions and reactions of humans, a species that acts quite irrationally most of the time and cannot be trusted to act irrationally in the same fashion most of the time.