I want to know the average wholesale price for software sold in the
UK, (the percentage split between the wholesale price given to
resellers and the end retail price. Also are any other conditions
common to wholesale, such as "sale or return", minimum quantities etc.
Also, as an example would say Amazon typically get a better deal than
other retailers?

We are considering selling a small software package through third
party websites and shops, we want to offer them a good deal, but not
give our product away. The likely retail price will be between £100
£150.

Any pitfalls would also be helpful.