These Keter Knit Cozies hanging basket plant pots are now £7.94 at Amazon. They were about £18 when I bought the last month, and have been slowly dropping in price but I don't know how much lower they will go. The price of the blue ones is still £16.31. These are not a bright white colour - more of an ivory colour.

It says they are small but they are actually a pretty decent size. You can remove the hanging bit and just use them as planters. I really like them :)

They also have a set of 3 small multi coloured planters (add on item) for £3.87, and the larger planters for £7.87/£8.93 depending on colour. Links in first post.