Tables used to be how everyone dived. Today, the majority of recreational divers wear a dive computer and they should.
A dive computer monitors your dive computers guide depth, time, speed of ascent, and NDL in the moment. Dive tables are a fixed calculation. If you go shallower during a dive, the computer recalculates. Tables don't.
Wrist-mount computers are what the majority of divers use now. They're small enough, readable underwater, and you can use them as a watch as well. Console computers are an option but fewer people go that way anymore.
Budget computers go for around $250-400 and handle everything most divers requires. Features include depth, time, no-deco limits, a logbook, and sometimes an entry-level apnea mode. Stepping up to mid-range adds wireless air monitoring, nicer readability, and additional gas modes.
The one thing people don't think about is algorithm differences. Some models are tighter than others. A conservative computer results in reduced NDL. Liberal settings allow longer bottom time but with less buffer. Both work. It just personal preference and how experienced you are.
Ask someone at a local dive store who's used multiple brands before buying. Good dive stores will have real-world feedback on what's good and what's marketing. Most good dive stores have buying guides and comparisons on their sites too