Am I paying a competitive rate to my Private Lender?

[Danny Price]

I invest in Tax Liens/Deeds in Alabama.  I purchase, rehab and rent.  I pay back the private money monthly calculated as a simple loan. 

I mentioned what I was paying to a seasoned fix/flipper that told me I was paying way too much. (14% on a 2 or 3 year loan)

Am I really paying too much? (compared to what other investors are paying? )

Is there a better way to structure the deal?  

Keep in mind I can't add liens to the property, and if previous owner redeemed, I make money from repairs and interest rate. 

So, I give promissory notes instead of liens.