I got a seed/plant catalogue in the post today. It features, amongst other things, a variety of onions. As you can see from this page, you can buy a package of 250 grams each of red, white and brown onion sets for just under €15. Or, for €20, you can get twice as much of each, exactly the same, if you buy them individually.
To be fair, they're not describing it as a special offer. But I reckon it's pretty special, myself.