The one I'm drinking right now is 6.76€ and the cheapest one is 1.28€.

First of all - what a price difference. Secondly, it's actually not bad. It does have that faint "cheap coffee" taste, but after a few cups I barely notice it anymore.

The real question is: is the tradeoff worth it? Do I give up a few percent of enjoyment on every single cup just to save the equivalent of a month's grocery bill yearly? I'm not in any dire financial spot - frugality is basically a hobby/lifestyle for me at this point - but it's getting rarer and rarer to find ways to pocket savings of this level anymore.