If you are going to be needing a cot bed mattress any time soon then it's a good idea to grab this now while you can. The Tutti Bambini Sprung Cot Bed Mattress was selling for £69.99 at Argos, and has now been reduced to less than half price. It's only £24.99 and has free delivery included as well! You're not likely to get a sprung cot bed mattress at this price again for some time.
This is an online only offer, so you won't find it in stores. As a cot bed mattress it's the size that is also sometimes referred to as a Junior Bed or Toddler Bed, but just to avoid having to return it make sure that the measurements are right for your needs. This is 70cm x 140cm, and is a sprung mattress with foam and is ventilated from the middle. The mattress cover is made using breathable Just-Tec fabric and has a wipe-clean surface. I'd still get a mattress protector to go on the top as well though, as we all know about potty training accidents!
My toddler will be turning two in a couple of months, and although he seems to be happy in his cot for the time being I will be getting one of these mattresses now as it's such a bargain. It will be needed for the toddler bed soon enough!
Many thanks to mobjw @ HUKD.