Photo is Chalcedony stalactite from Guanajuato, Mexico
Before I discuss making large purchases of collections, warehouses and buyouts (next post) I should mention the tools of the trade.
Here is what you need to carry in your mineral buying daypack.
Good hand lens
Notepad and pen - ok I have tried the PDA or the phone it is just not as good for quick notes as a memo pad and pen. Sometimes there may not be a label or the dealer has information not on the label that you will want to record. Even if there is a label I write it down in case the label is misplaced. I also write down the price paid which is more important for a dealer but may become important in the future for appraisal purposes
I carry a calculator other than your phone. Calculators passed back and forth between you and the dealer are wonderful negotiating tools. Plus not all dealer's first language is English.
Wet wipes Handling rocks can be dusty work.
Water and munchies so you don't have to leave in the middle of a good show.
I carry a bit of newspaper. At smaller shows not all dealers/swappers are equipped to wrap minerals. I don't get bent about that I just come prepared
And we carry boxes in the truck to stash everything for the ride home. If you collect small items you may want to carry tissue and small plastic bags.
And dollars, lots of dollars. Of course at big shows most dealers take credit cards and checks but not as much at smaller shows and swaps.
Remember to wear comfortable shoes
I look forward to meeting you some day at a show