Tables used to be how everyone dived. Today, the majority of scuba divers dive with a personal dive computer and they should.
A dive computer calculates depth, bottom time, speed of ascent, and NDL in real time. Tables can't do that. If you move between depths mid-dive, it updates. A table can't.
Wrist computers are the most common read full article buy at this point. These are compact, easy to read, and you can wear them as a daily watch too. Console-mount computers are available but not as many divers go that way anymore.
Basic computers start around $300-odd and do everything the average diver requires. Features include depth, dive time, NDL, a logbook, and sometimes a basic freediving mode. The $500-800 range gets you transmitter compatibility, better readability, and additional nitrox modes.
What new divers forget is algorithm differences. Certain computers are more cautious than others. A cautious setting means less no-deco time. Liberal settings allow longer bottom time but with less safety margin. Neither is wrong. It's your style and your diving background.
Talk to someone at a dive shop who dives with various computers before buying. Good dive stores will have real-world feedback on which ones hold up versus what's just marketing. Most good dive stores have gear reviews and comparisons on their sites too