I need a cheaper funding source

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 I just bought a property a  month ago. I bought for 17k With a hard money loan that doesn't use a balloon the interest rate is 15.9% (I need cheaper money). It will be paid for in 5 years. I had to buy a years worth of insurance and list them as first lien. I got about 8500 on my lowes card in supplies alone on this house and I hired some help by the day all out of pocket. Monday I had a guy come by and give me 10k earnest money. The terms are sales price 109k. on a 30 yr note no balloon at 10.4%. the payments to me will be $898.20. MY payments to the hard money folks is $412. 

Due to being self employed/ non-predictable income I'm unaware were to get low cost money that is not connected to my income and/or tax return. I have close to an 800 credit score.