It looks like /data/cache is mainly used by Market for storing downloads. Quite a bit of space can be taken up there. And it looks like one can just relocate that to storage (with root);
rm -rf cache
ln -s /mnt/storage/cache /data/cache
/data/cache won't be available for any apps that need it directly on boot, and those apps may crash, but I haven't noticed anything like that happening on my A43.
As usual with such tricks, use at your own risk and make a backup.