You can use the Ubuntu Server installer, if you select during the installation to install servers later on it will install the bare minimal to have a running Ubuntu installation without having to go thru manual configurations.
I would recommend this over other solutions because:
- It will leave you with a running system with minimal services running
- Minimal configuration necessary, installer will do the work for you
- Very easy to install
- Without running many service the memory / CPU footprint in the host
will be minimal
The performance of the VMs will depend on the host specs but since you have no GUI and almost no services running (unless you want them installed and running) the necessary specs for the host will be very low.
You will be able to run a few of these inside VMs on a normal day to day computer (for testing / development purposes ofc).