Is the $16,000.00 value for real or is it in your head, and do you have the emotional fortitude to tell the difference. If you have a buyer who is looking for that specific coin and willing to pay the price, then $6,000.00 just made your rent, payroll, taxes, and all the other things you get to deal with. You asked about whether or not $10,000.00 is sufficient operating capitol for a B&M shop. That would depend on your level of expenses and volume of trade. It is better to have 1000 small trades that one or two big ones. I have never run a retail outlet, but I have owned a business. Keep in mind that any business is like a hungry child, and it needs to be feed. And you are the last one to get paid. Also, never trade a hobby you love for a job you hate. If you enjoy negotiating trades, love working with people, are knowledgeable in your field, can deal with the business side of business, and above all are ethical and honest, then it doesn't matter where you start. Life is scalable.