You need to save up the funds.

One of the main reasons for this is let's say the lender were to lend off a value that is tethered to how much the property can earn as an STR, and they're at 80% LTV let's say.

Also, let me know if you’re ever exploring partnerships or raising funds for a deal—I believe in combining efforts to scale faster and smarter.”

Quote from @Juan Ruben Cortez: I believe the funding fee is 0.5% of the remaining loan balance, plus maybe another $500 - $1,000 in lender fees. 

Meaning you may be able to do some cosmetic or smaller renovations like bathrooms or kitchens in your duplex when the tenants turn over and those smaller investments can demand higher rents, so in the longterm you may have more cashflow from the duplex to help fund a future investment in another property while you wait for market conditions to change.

He took a 401(k) loan to fund the down payment on a four-unit building in a rapidly appreciating neighborhood.

I have been funding these types of props since 2002 for a turnkey company in Detroit who used LA based sales agents then over the years I have met most all of the Marketing companies or they have sold clients of mine props I see the commish on my huds. 

They can be great tools for funding acquisitions and supporting the BRRR strategy, especially for multifamily properties. 

I would like to invest in there funds below1.

Also, hard money lenders want a scope of work filled out prior to funding the deal so this is a good little hack to get one as well.