I wouldn’t take them in the plane, that sounds like a bit of a nightmare. Can you share where you’re going? You will need to look into how customs works. If they’re over a certain value they might need to be declared and it might not matter how much you paid for them but rather how much they’d be judged to be worth in the country you’re travelling to.

I lived in a third world country for a while where some things you couldn’t get locally were really expensive, even if they were cheap at home. I imported some costume jewellery which I paid £23 for and the locals wanted me to pay £100 for it to be valued and I was told it would likely be valued around £200 so I’d have to pay import tax at around £80. I just let it get destroyed as it wasn’t worth the cost or hassle.