Seller wants extra to package item

So they had a quoted price for shipping, but are now wanting more?

Sure you could insist they send it for their quoted price but then you would have to weigh that up with the possibility of the item being damaged during transport. If the price (including the extra packaging) is still one you are happy with then I would probably consider paying it. But also remind the seller to be more careful with their quoted costs in future.

Maybe as an alternative you could suggest a different method of packaging that doesn't cost anything. I have managed to send my items for the last few years with no material packaging costs. Boxes are free from supermarkets. Scrunched up newspaper. Reused plastic bags. Exactly what is he/she wanting to use that costs?

I have organized shipping and paid for myself , more his time for packaging it really by the sounds

I think it's reasonable to charge for packaging something as an alternative to a buyer directly picking up, and it's certainly allowed by Trademe and they even differentiate between shipping and packaging costs. If someone wants to pickup themselves, then no packing or packaging is needed, although I usually find a box to put things in or a reused shopping bag, but having to pack something that a courier is going to collect is a very different matter. On the rare occasion If I am arranging a courier to collect something for me, I always offer to pay a bit more to the seller to cover proper packing and packaging if needed so the item arrives to me in the condition it left the seller, which I think is quite fair.

Shipping is simply the cost of the courier picking up and delivering and only forms part of the total cost of collection & delivery, hence the commonly used terms P & P (Postage & Packaging) or S & H (Shipping & Handling).