I have read that a flat rate box holds $100 pennies, however I can't afford that many pennies initially, maybe like 75 at most. So do I just ship what I can get when I sell it?
$75 actually works better for the flat rate box.. weighs 52 pounds. You don't want to be trying to carry much more than that at a time. Your first shipment will probably be just one or 2 $25 boxes until you build up your reserves a little.
When you get ready to do your first shipment I will be happy to guide you step by step on the proper way to package them for priority mail shipment. You want to make sure you package them properly so there are no problems with the shipment. I have been shipping pennies for a long time. I shipped over 2 tons of pennies this way last year.
If your percentages are low.. just sort more. If your percentages are high.. just sort more.
Now selling Copper pennies. 1.6x plus shipping. Limited amounts available.