I was in the Auto Parts business a life time ago and 30% was a pretty standard markup. I should think a wholesaler would be thrilled to get their product exposed to hundreds of millions of users rather than have their product packaged and setting in the bottom shelf behind the TV’s in any number of big box stores.
Dunno about retail software, but in the book publishing biz, the publisher generally only gets 30-40% of the cover prices from the distributor, who then sells to retailers at about 60-65% of cover price. A rough, but not too inaccurate, breakdown is 1/3 publisher, 1/3 distributor, 1/3 retailer.
The specific terms vary based on size and reputation of the publisher, can unsold copies be returned, etc.
Digital publishing, at least that which I’ve been involved in pricing, expects the digital version to be 50% of the price of the dead tree version, with the publisher getting about 70% of that (roughly the same amount per sale as print distribution).