For things that are relatively cheap - under 10 lv. I pick up the most expensive per kilogram or the second best. For more expensive I look at the label and try to see the ingredients, look at the packaging etc. I look if the manufacturer have ISO or HASSAP certificates, Stara Planina or similar.

Billa and HIT in my oppininon are in different categories - HIT is better than Billa for most of the stock there.