What is being described here are various versions of a Self-Inflating Mat, or SIM.
Some people prefer traditional blow up beds, some people prefer SIMs.
SIMs are much warmer to sleep on because they are well insulate with a layer of memory foam, with additional air inflation, so you do not get the cold from the ground. Blow Up Beds simply conduct the cold from the ground, and your body heat back into the ground.
SIMs are more omfortable the thicker they are and also generally ore expensive with each Cm of thickness.
Aldi currently have 5Cms which many people find fine - and they are more than fine for kids, who are lighter. Otherwise you could look at 7.5Cm or even 10Cm, but 10 Cm is getting pretty costly.
Look at places like Millets online for good deals.
You can try SIMs at a places like Decathlon or GoOutdoors.
If you prefer sleeping on a blow up mattress, you can add insulation by putting fleece blankets under your sleeping bag, or putting interlocking foam mats on the floor of your tent, for example.
Some people put SIMs on top of camp beds, but for me that is just extra stuff to take, extra expense and the non-rigidity of camp beds gives me back ache.