This set of Forstner bits from Amazon is very cheap. You can drill holes with them but out of the box they don’t work very well. After sharpening them with a small diamond plate they work surprisingly well.
What I would recommend is to buy these as a starter set and whenever you find yourself sharpening one of the bits over and over again buy that particular bit from a better brand. Just be aware that 2-3 high quality bits will easily cost more than this entire set.
Cost of this article are around: 40 EUR
You can purchase the article under the following links: