On thing you may want to consider is instead of selling at such a low price,
why not just combine all your new with your used? You will get a much better
return and your inventory will increase which will also increase your sales.
Your customers will be very happy because all though they are buying used the
quality will be new.
I know there is one store who sells all their new and used parts as used. Their
advantage is that they have a huge inventory so they can charge more than the
6 month sales average for new parts and still get allot of sales (I know way
more than us).