Hi Reinier,
I just bought a Lenovo M90n with I3-8145, 8GB ram and 500GB SSD for 299€ at amazon.de (Germany)
The installation is described here. There is a slot for a 2nd M.2 SSD so that you can use it also with internal storage for music files.
I am very pleased with the form factor and the price snd so far also the performance is good for my needs.
regards Chris