I've had a few tripods over the years. Work-Horse is an old aluminium Slik 88, I bought 2nd hand about quarter of a century ago.
But I had a similar dilemma before Christmas, pondering purchase of one for my daughter for her school photography. Eventually found another 2nd hand Slik 88 on e-bay! Convenient, as she was already familiar with it. But I digress...
Three basic 'sizes' of tripod; mini, or table-top, is conveniently pocket-able and portable, and provided you can find something to purch it on, like a car roof or a wall or a picnic bench, can be fantastically 'convenient', though they tend to struggle to support a camera bigger than a compact. I have a couple and little gorilla 'copy' I got the o/h was useful enough to support a bridge ad just about my, more compact D3200, with the kit lens on it. For a few quid? I would reccomend one as as good a place to start as any.
I have a little Hamma one that is about four inches long when folded, and has probably been used more than any of the others, simply because I have it with me!
Next up you have a 'field' or travelling tripod; usually reach about waste height fully extended; typical things you'll find on e-bay for about £20. They tend not to be particularly sturdy or stable, but then you don't want anything to heavy to lug about if you are hiking up and down mountains taking landscapes.
Fully extended height, is probably not all that important, unless you don't like bending down to look through the view-finder, and the more they extend, so the heavier they tend to be, and or more flimsy.
My favourite field tripod is an old 1960's 'telescopic' one of unknown brand! Collapsed it's only about 18" long, and quite light. Tublar legs have three sections that slide out and latch with spring clips, in three sections, and no 'bracing' or anything between. It's very simple, very quick and easy to use; lop out the legs, prop it on the floor and level the camera on the ball head. Its 'faff-free' and I like it! Made of old fashioned tin and brass, its does the job! You can keep your carbon fibre thanks!
Little bit 'wobbly' on a windy hill-side, but you hang your gadget bag from the head, to help hold it down and lower the CofG.. works a treat, and that old pod has propped up some pretty hefty old film cameras in its time; its more than up to the job of supporting a modern plastic electric picture maker!
Of what is on offer, new, these days.. blugh! Scaled down, made down to a price techno-wonders trying to look like more sophisticated and less useful studio tripods, I think....
The Slik, is much larger, and more cumbersome, 'studio' tripod, and fully extended can support a camera almost at eye-level; company actually started out making tripods for TV cameras, and mine, dating to the late 70's/early 80's was sold as a cine/video tripod. if you are more keen on shooting video, then a taller pod, with a 'smooth' pan and tilt head, may be more important to you, but if so, don't bother with anything off e-bay, and expect to pay well into the £100's for a smooth movement head.
Larger, heavier, and generally more cumbersome, with bracing stays and levelling adjustments and the like making it much more of a 'faff' to set up, this sort of tripod will probably not be taken out and about so much.
Which brings me back to what's on offer these days, and I wold suggest, as a starting point you paruse your local camera shop, if there is one still, and fiddle with stuff! If not have a look at e-bay.
A field tripod is the most versatile and most likely to get 'used'; and without pushing the boat out, £25-£50? You'll get something 'useful'. Should support a DSLR well enough; and you don't need anything 'fancy'; I wouldn't be too bothered about how much bracing they claim to have or how high they extend; I would be looking for 'simple' and easy to use, and something not too bulky to lug around. At this end of the market nothing is going to be hugely heavy, so I wouldn't be over bothered by a few grams difference in weight, when I have four hefty lenses in the camera bag!
And I would treat it as 'disposable'; if yo take it out and about, its likely to get pretty battered, and darn site less gauling to knacker a £30 tripod than a £300 one! Meanwhile; Treat it as a learning tool; see how you use it; what irks you about using it, and plan to buy a 'better' one at a later stage, when you can be a bit more strategic, and this one, if its ot knackered can be retired to be used as an off-camera flash-stand, or 'spare'.