I don't mean to be a killjoy, and this may sound like complete blasphemy here at Bladeforums, but at the age of 21, perhaps you should be using/saving that $400-$500 for something other than a knife.
Not that it's any of my business, but I wonder who is paying your bills/supporting you. If you are working and completely financially independent, then that's great. But if your parents are still supporting you, giving you money, paying for school, paying for a vehicle, paying for insurance, etc, etc, then perhaps that $400-$500 could be better spent elsewhere. After all, it's not like anyone needs a $400-$500 knife.
I'm 45 years old, and it wasn't until I was 31 that I started indulging myself on expensive luxury items. And I only started doing that once I became financially secure, with a good job, no debts, and plenty of savings in the bank to cover the sort of unexpected expenses and emergencies that are inevitable in life.
Back when I was single with no dependents, my policy for personal finances was this- after I paid all my bills for the month, whatever I had left over I would split in half. Half would go into the bank never to be touched, and the other half I would spend on "fun stuff". Sometimes I would save up the "fun stuff" money for awhile so I could afford something more expensive.
I know that paying bills, paying off debts, and saving for future necessities isn't nearly as fun as buying an expensive knife, but having $400-$500 in the bank when you REALLY need it can be worth far more than any knife.
But of course, it's your money, and you are free to do whatever you want with it without any judgement from me. And for all I know you might be completely financially independent with no debt and a good paying job. I just can't help but think of all the people I've met around your age who are drowning in debt, struggling to pay rent, gambling without health insurance, and living harder lives than they have to because they weren't more careful with their money.