Main features to look for in keyboards
1) Full size keys, not “mini” keys. This is crucial.
2) “Touch sensitive” keys. So dynamics can be played with varied finger pressure.
3) The ability to record so the student can playback their own performance.
4) “Weighted keys” (as opposed to “semi-weighted” or “synth action”). These are generally only available on the larger, full-size keyboards, in which case you’re better off looking at this guide to keyboards better suited for private lessons.
Some recommendations
Yamaha PSR-E283 – Bare minimum. It’s not touch sensitive, meaning dynamic control isn’t possible. It also doesn’t have weighted keys (no keyboards this size do). But it can record, which surprisingly many keyboards can’t.
Yamaha PSR-E383 – Like the E283 above, but with touch sensitivity, worth the extra cost.
Casio CT-S1 – Like the E383 above, but with a more sleek/minimalist design and fewer distracting buttons. If taking private lessons or practicing a lot, a full size keyboard with 88 weighted-keys is important, but in a pinch this keyboard (or the E383) could be adequate for roughly the first year of study.
Yamaha P45 (AKA P71) – There is a big price increase here, but this is the next step up, with 88 weighted keys. It can’t record, but a keyboard like this would generally be adequate for a couple years of private lessons. If a student really takes off they might need a decent piano before too long. Here’s a guide to keyboards better suited for private lessons.
Premium keyboards
As keyboards go up in price from here, their keys tend to slowly improve, getting closer to the feel and control of a real acoustic piano. Brands to look for are Yamaha, Kawai, Casio, and Roland. Just keep in mind, to get really close to the feel of a good acoustic piano, you’ll need to spend thousands of dollars. It’s possible to find a good used acoustic piano for the same or less. Decent acoustic pianos can sometimes be found for free. Here’s a guide to finding a free or inexpensive piano.
Keyboard stands
Unless you have a perfectly low table for the keyboard, a stand is very important. Some keyboards come with stands, but most stands don’t actually go low enough for a kid (or adult) sitting down. There are many on the market, but this “Hamzer” X-style stand is decent at a reasonable price (or for just a little more this no-assembly one is better yet: Hamzer welded). For full-size weighted-key keyboards, a more sturdy stand is highly recommended. Look for more sturdy X-style stands, or better yet, “Z-style” and “table-style” stands which are typically best. “Table-style” stands are also known as “platform-style” — this one is even better still.