Prices have really gone up in recent years, I notice it too when I do my shopping. Anyway, for frying, what you get at Lidl works just fine - the point is that for this specific use you don't need anything fancy. The important thing is that it has a good smoke point, otherwise you risk burning it and ruining everything. But one question: how many times a week do you fry, more or less? Because if you do it rarely maybe it's still worth picking something good quality, but if it's something you do often then the reasoning changes.
Like others have said, Lidl and Coop are fine, but if you want to try something else without spending a fortune, you could consider sunflower oil instead of the classic mixed seed - it often costs about the same but tends to be a bit more stable to heat. I personally use whatever I find at the store closest to the office when I remember, and honestly I've never had any problems. There are periods when it's worth stocking up a couple of liters if there's some deal on, anyway.
For the rest, don't kid yourself that the more expensive brands make much difference for normal frying - if you're not a restaurant frying all day, the savings are better spent on something else. The only thing I'd advise is not to reuse the same oil too many times, because that's when you really start ruining everything.