An old technique but good to remind newer players.
Also, for those who have access to it, the Founders world offers a further discount on ship prices which can make quite a large difference in purchase price (millions, literally) as you get into the bigger ships.
I was extremely tired on day and decided to sell my Asp, but i accidentally sold my 5 million credit cobra and I was pretty sure I lost some money. I didn't realize it was 10%