[The Detroit Collector]

I agree walking around with that type of money is nerve wracking. I will say this, CASH IS KING. Some dealers would even be willing to lower a price if it is all cash. One thing you can do, if you dont like walking around with that kind of money is researching to see if your bank is located near the convention center. If there is something you like which is expensive, you can ask the dealer to put it aside and go to the nearest bank to take out the money.
It would also be smart to walk around with a backpack, or even a card holder locked case which you could put cash in.

Next best option aside from cash is Venmo, CashApp, Paypal. Make sure you are setup with those.