Years ago, dive tables were how everyone dived. Now, nearly all recreational divers use a wrist-mount computer and they should.
The computer monitors depth, bottom time, ascent rate, and no-deco limits in real time. Tables can't do that. If you change depth during a dive, it updates. Tables don't.
Wrist computers are what most people go for now. They're visit this small enough, readable underwater, and you can use them as a daily watch too. Hose-mounted models are available but less buyers go that way these days.
Budget computers start around $300-odd and do everything most divers needs. You get depth, bottom time, no-deco limits, dive logging, and often a basic freedive function. Mid-range adds wireless air monitoring, nicer readability, and extra nitrox modes.
The one thing new divers don't think about is algorithm differences. Certain algorithms are more conservative than others. A cautious algorithm means reduced bottom time. Looser algorithms extend time but with less safety margin. It's not right or wrong. It's what you're comfortable with and how experienced you are.
Ask people at a dive shop who uses various computers before you decide. They'll have a straight answer on which ones hold up and what's hype. Most good dive stores put out buying guides and comparisons online too