I mean, in a can with 400 g of content, 50% of the product can be water or other filling material. In another product the fill-content can be 25% but at a higher price. Often these prices actually evens out, or the supposedly cheaper product is actually more expencive.
This can also be applied to other products than food, just in different state of breaking faster.
Germany is full of these types of stores, Aldi's products feel like a bit more quality than the rest when you talk to people. Some people does a run on mondays and thursdays to Aldi, Lidl, Extra, Plus, Norma and so on, that all get different products every week. Some of them twice per week. If they don't get sold within a week, they get moved down further towards the exit, at even cheaper prices when the new stuff comes and gets placed at the premium area.