I feel something like 1 point origination and 10% interest would be fair. 1st lien position secured with deed of trust, max loan amount of 75% of ARV.

A wise investor might ask some of those folks if they'd rather earn 3% on an investment secured by real estate. 

I’d want to be partners in everything… if you are able to secure financing or some other value, you should be rewarded for that in the deal somehow.

This is where my question comes: How can an 18 year old secure invests for a commercial deal?

Most humans, once our basic needs and security are met, are far better off in life by measuring incremental joy than by measuring incremental financial returns.

Definitely get that legal opinion, not just on the OA but on whether this is offering a security or not.

The seller got really mad over something and kept the security deposit.

@Kevin Kohler was looking mainly for typical residential HeLoC access with the property securing it.

IE: House Hacking - 1) Identify a 2-4 unit property I can live in and rent the other units such that net rents cover most of or exceed the mortgage payment, goal: live rent cheap-or-free; 2) Secure long-term fixed rate mortgage/debt; 3) Hold and live in the property as I focus on honing my property management systems/skills and accumulate of capital for the next deal.Step 2: Call financial institutions (local banks, I'd start with Happy State. credit unions, Frost, etc) and figure out financing options for your chosen strategies.

Even hard money loans without your home being used as security like a HELOC loan.