Last week Tesco reduced some of their Frozen clothing, and this week they have reduced more items, mainly nightwear. There are now pyjamas from £4 a pair, nightdresses from £6, and a dressing gown for £8.
The Olaf onesie is also reduced down from £12 to £8, and in the nightwear section, but I'm not sure that this would be suitable for wearing to bed, especially with the big warm hood.
The sizes available vary with each style, but some of them have every size in stock at the moment, though they might not stay in stock for long as they are such good value.
All of them can be delivered from £3.95, or you can click and collect for free.