Some useful answers here so far.
For a moderately priced bottle, Johnnie Walker Black label is a good option. It won't break the bank, but is a decent whisky to drink neat.
You could get a small tasting set like this one:
https://www.houseofmalt.co.uk/product/regions-of-scotland-whisky-tasting-set/?gclid=CjwKCAiAlO7uBRANEiwA_vXQ-wtd9feyAe89sGTzq8jhjldMfkkYmMsf7KUdntEAqXJWQvU_J5FxOxoCvBsQAvD_BwEIt's terrible value for money but not much worse than an advent calender in terms of price per litre. However it would give you an idea of what whiskies from the different regions of Scotland taste like... They are very different!
As a Scot it pains me to recommend this one and it is on the pricey side given that it is a small bottle. But Nikka From the Barrel is a fantastic whisky.
https://www.waitrose.com/ecom/products/nikka-whisky-from-the-barrel/460553-353692-353693My father and uncle are both whisky fans and they rate it highly. I've taken a bottle to share with friends where we all brought a couple of bottles and it was by far the quickest to disappear.
As a final caveat, if you plan to drink it straight, I'd avoid anything you see behind the bar in a basic pub (E.g. Bells, Grants or bourbons such as Jack Daniels, Jim Beam) but if you do plan to mix it, then you might as well buy something cheap as a mixer will mask the subtle flavours that you pay more for.