True private money is going to cost 10-12% plus deal equity which often makes the true percentage 20-22% on your money vs alternative lending which will be around 12-14%.Here to chat if you want some help comping a deal and putting one together. 

How do you deal with the stress of ownership.

Many times they will claim it's wonderful and then try to hide their worst deals by only showing completed deals.

if it is just the financial side holding you back - let your bank be your partner… or see if you can borrow the money from a family member who knows and trusts you -  without actually partnering with them on the control of the deal itself (pay them interest - or even bring in on the lien to secure their position the first time) - but let them be the finances and you control the project. 

Maybe % of purchase price (though that would mean low estimates for killer deals, and higher estimates for hot market properties)?

I was stunned by how much the county government assessed vacant lots for.

TIAHi Quynh, sounds like a great deal! 

I am ok to leave some money in the deal.

You should keep it to yourself though, if you get all the BP'ers buying in there, you will have more competition, fewer great deals for you :-)

You also don't have to deal with any STR regulations since you're a 30 day+ rental.