Upload & Sell: Off
Use/abuse your CPA on this one. Most audits will treat you respectfully but make no doubt, they will dig up -everything- pertinent and if your records aren't tight, it will cost you money and time.
Remember - a tax agent can tell you BIG lies - and get away with it. You can't, or you get nailed.
That being said, the advice by others about bringing your CPA is spot on.
This kinda sounds like a sales tax audit. They will want every trade invoice, every bill you issued, and all your checking info.
And, don't forget, they have access to sales tax info from many states on what you purchased.