Is there any good site that comperes margins on-line? There are big difference between 20+ or 10% interest rate yearly basis.
Have you ever tried margin trading on Poloniex, there you can set margin commissions from 0.02%. but usually the minimum commission is determined by the lender, sometimes the commission changes at a higher rate if the market starts crowded, and conversely with a low commission rate we can find if the market starts to quiet.
Even now I run a margin on Poloniex with a maximum commission of 0.02%.