You can also check online resources like BiggerPockets or Roofstock, which offer general CapEx guidelines based on property type and age.These methods should help you perform a solid preliminary analysis.

@Keetaek HongI use QuickBooks Online (QBO) for my flipping business, rental businesses, and bookkeeping clients.However, many on the forums will advise against QBO.

If there are barriers that limit similar supply and you figure out how to get the housing units online, even better. 

If you purchase online, find a retailer that has the delivery window at the point of purchase.

I’ve found success by networking at local meetups, connecting with real estate agents, and exploring online platforms to discover these opportunities.

A good tip is to reach out to contractors, visit local supply stores, and check out online resources for cost ranges.

When I did an online search for commercial multifamily lenders, most have a minimum lending requirement of $1M and I don't need that much. 

A lot of that is referral based or people find my site online, organically. 

Quickbooks online could work for what you need.  

I just can't find ANYTHING online that isn't from Chris or his team.