Zipchem bag [Purple Clonk]
It can be sold as a single item (based on recent changes I think it should properly calculate the value of things inside). You can open it to get the contents out. To cut down on bloat, maybe when you remove the last one, it asks if you want to throw it away, like empty six-packs.
This would cut down on the amount of spam involved in large drug transactions, especially those that take place in public places like bars. While it's true that there are some items which help with this, they feel a bit more permanent and aren't easily used for selling in stores / for transactions where you'd want something disposable. It would also allow chemists and other drug sources to add a bit more identity to what they are selling.