I misread your initial statement, my apologies.
But, on point, the amount of gold saved by item crafting turns one wizard level into hundreds of thousands of gold for the party, which seems to heavily out weigh the costs.
As I pointed out earlier per RAW you can't make money on crafting magic items
PHB pg 112
In general, a character can sell something for half its listed price.
Characters who want to upgrade to better armor or weaponry, for
example, can sell their old equipment for half price.
So when you character "sold" items to the party - he pretty much went into house-rule territory (disregard any use of common sense when attempting to analyze the rules, it only leads to madness
