Speakers Paper Cone

[Upyourface]

So I recently bought some speakers off eBay for a great deal, it says the only damage is cosmetic and that they're fully functional which is great because they're worth around £650 and I got them for £20.99 (+£25 roughly to hire a courier).
But it says the central paper cone on one fo the sub woofers is missing and I'm wondering whether or not it's a big deal.
Should I try and find a replacement? How much will that cost? How would I fix it? Or will there even be a problem at all?

Anyone help me out?

Pic related, it's them.
And here's the auction incase anyone needs any more pictures/details.

[Upyourface]

Forgot Pic