Curling tongs or straightening "things" for DD?

[AdoraBell]

DD likes to straighten her wavy hair, but also wants curls some times.

Should I buy her curling tongs or will a slim straightening thing, tech term, work for both? I'm clueless.

TIA

You can curl hair with straighteners so I would think they would be the best option, two styles for the price of one thing! There are youtube tutorials and things for how to use them for curling rather than straightening

Thank you, I was trying avoid buying two things, will have a look on youtube.