It looks like the guys (and/or girls) have made an addition to the page on which you can read about their free Express version for Linux. As I told you about the limits of only one CPU, 5GB of disk space and 2GB of memory, they now add:
Please note that these limits apply to each instance of ASE Express Edition. You can have many instances of ASE Express Edition running on a machine (e.g., a multiprocessor machine), and hence in total, all of these instances could utilize more than one processor, more than 2 GB of RAM and manage more than 5 GB of disk space.
So, if you have a bigger machine, and don’t mind running multiple instances, this could be a very cheap solution.