If you want to practice sending morse code a practice oscillator is very useful although of course you can use the side-tone of your transceiver if you have a transceiver. Practice oscillators come in all shapes and sizes, can be very cheap but nowadays often come with more than just the oscillator functionality. There are a number of units sold by Phoenix Kits which are oscillators and morse tutors and also keyers for morse paddles.
As mentioned above there are many cheap morse tutors available, bother fully built and as kits. There are also the old style tutors such as the Datong D70. As a project our club made a modern Arduino based Morse Tutor.
The Morserino is an all-in-one Morse Code training and practicing device. It includes an oscillator, keyer and built in paddle, it also has various morse tutor options, Kock trainer, echo trainer for sending etc. On top of these features it has wifi capability for practicing over the internet and is a LoRa transceiver for practicing with other Morserinos nearby. The Morserino requires some self assembly and soldering of a few of the larger components.