I require 20% of the total cost of the instrument plus all shipping and taxes.
I charge .6% interest per month, so if you choose to take 12 months to pay off your instrument, you'll be paying 7.2% interest for that year.
HERE'S AN EXAMPLE OF HOW IT WORKS
Let's say you live in Ontario and buy an instrument for $5000. Perhaps you live in Ottawa and I ship it to you there for trial. Shipping would cost around $25. Tax of 13% HST costs $653.25, so the total is $5678.25. You decide to take 18 months to pay it off. Your downpayment will be calculated like this:
20% of $5000 = $1000.
Shipping = $25.
tax on $5000 = $653.25
You send me an e transfer or credit card payment of $1678.25. Subtract that amount from the total of $5678.25 and you get $4000. That's what you have left to finance. Now you multiply 18 (number of months for financing) by .6 and you get 10.8%. Add 10.8% to $4000 and you get $4432. That's the amount left to pay. Divide that number by 18 and you get $246.22. That's your monthly payment.
You can plug any numbers in that you want, but that is my formula.