At time of writing, this is the only complete tenbou pack purchasable on Amazon.co.uk website. Link to product and pictures follow.
You can buy a set of 88 tenbou from Amazon.co.uk here.
For £10.95 (Free delivery on orders over £20), the set includes;
A total of 88 tenbou.
This gives the option for players to play with either 25,000 or 30,000.
Total cost works out to 0.12GBP per tenbou.
With that in consideration, I would say that’s actually expensive.
You can see in the pictures, there were some tenbou that had extra dots and the paint wasn’t exactly within the circle.