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Anything like that?

i.e.

Buy product X for $20, sell it for $50 etc.

Curious as to what functionality you would like to see other than what a spreadsheet provides?

Some sort of accounting package that automatically pulls that data in etc?
 
I think he wants an app that tracks listings on Ebay and for the app to determine if each item at the asking price is profitable if purchased, then sold.
 
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