If you need to generate invoices from your AliExpress purchases,
Alix is your best free solution!
Alix is a chrome extension that integrates with AliExpress site and adds a 'download invoice' button next to each purchase item in your purchases page.
Just click on that button and you'll have your invoice ready for print or share in a few seconds.
The professional version of Alix is a work in progress.
Feel free to let me know if you have some special requests for the next version.