I suggest you save some money, and buy a cheap house for cash, fix it up and get it rented. Then cash out refinance on the rental and buy 2 more cheap houses. Repeat many times.
A conventional mortgage will typically need 20% down. If you owner occupy you can get 3 or 3.5% down which makes this a good option if you can get a multifamily that you'd be willing to live in for a year and rent out the other units. The hard money lenders I've talked to will typically finance 75% of the loan plus rehab of your first deal. Once you build a relationship with them through multiple loans they'll increase the percentage up to the full amount. Private money will have more flexibility but at a cost. You'll also need to gain their trust which will be difficult if you don't have a track record and aren't putting much of your own money in the deal.
I would start with an owner-occupied property. House hack it to significanlty reduce your monthly expenses. Save up and by an exclusive rental property. Rinse and repeat, and refinance to pull money out as you can. Happy investing!