Here some shoe brands with many offerings under 150€:
- Xero Shoes (USA)
- Freet (UK)
- Magical Shoes (Poland)
- Vibram Fivefingers (Italy/USA)
- Revivo (refurbished Vivobarefoot shoes)
- Feelmax (Finland)
- sandals! Barefoot sandals are expensive for sandals, but can be usually found under 100€ (Shamma and Earthrunners are my favourites, both from the US)
These are the ones from the top of my head, there could be other good options.
Furoshiki (mentioned in another comment) are nice but have a narrow sole, prolonged use causes me a bit of pinching due to the stretchy material.