So, in that rare case like selling an oppo 205 we can say “buyer to pay shipping, PayPal fees and estimated income tax due”.
OR
You could ask for interesting trades of "X, Y or Z" or you could ask for your basis and ask that the buyer donate $X to a charity (of your choice) and include the charity receipt with their payment prior to shipping. OTHERWISE, someone would be trying to EVADE income taxes rather than to AVOID or DEFER income tax. Quite a different matter.