Years ago, dive tables were the standard. At this point, most divers wear a dive computer and for good reason.
The computer tracks your depth, time, speed of ascent, and no-decompression limits in the moment. Dive tables are a fixed calculation. When you change depth during a dive, a computer adjusts. A table can't.
Wrist computers are what the majority of divers buy now. They're compact, readable underwater, and you can use them as a daily watch as well. Console-mount models are still resources around but not as many divers choose them anymore.
Budget computers go for around $250-400 and handle everything most divers would need. They give you depth tracking, bottom time, NDL, dive logging, and often a basic freedive function. Stepping up to mid-range includes air integration, better screens, and extra nitrox modes.
The one thing people don't think about is algorithm differences. Some computers are more conservative than others. A conservative setting means shorter bottom time. More aggressive ones allow longer time but at reduced safety margin. It's not right or wrong. It just your style and your diving background.
Check with someone at a local dive store who uses multiple brands first. Staff will have honest opinions on what's good and what's just marketing. Most good dive stores have buying guides and comparisons online as well