- Workaround found - Custom fields: stock handling on parent item

[kalestud]

Hi there,

we have a webshop in single items (vintage hats).
When people order a hat, we'd like to offer the hat with or without "2 strips of cork".

So I created a custom field 'include cork strips :'
On the product I let the customer choose NO (standard) or YES (+ €1,00)

Problem is, when someone orders this hat without cork strips, you can order it again with cork strips!

Is there any way to overcome this? We have over 2000 unique items 
Thinking the stockhandle should be on the parent, can't find the right function 'though

Also: how do I show the additional price including tax on the pulldown?
(hiding it over here might also work, I'll just state the cost in the option name)

VM 3.2.2 on Joomla! 3.7.4

[kalestud]

Oh, by the way, simply adding a product 'cork strips' and make that show up in the cart was also a nice idea, but...

we give people who buy 2 items a (shipping-)discount of 3,50, so if people buy a hat ánd the cork strips, we give a discount of 2,50 instead of charging them a euro. 

[kalestud]

Created a work-around.

All hats are set to be 400 grams and by creating a product 'cork strips' and setting that to 0 grams, I can setup shipping rates by weight.
2 hats = 800 grams, with or without cork strips.