Huge differences in sims.Mainly in the construction and thickness.Some singles also come in extra wide.
A 3cm sim is going to be nowhere near a comfy as a 7.5 plus one, especially if you're laying it straight onto the ground. Some cheap ones that are basically a slab of foam, are also quite firm (too firm for me), and bulky when rolled.
Some of the more expensive ones, like the Exped MegaMat 10 offer good insulation properties as well, (nothing going to make you more miserable at night than being cold), and take up relatively small amount of space when rolled up.
Outwell Dreamboats seem to be being talked about a lot at the moment, but they're well over £100 for a single.
I've just bought a Vango 10cm sim, as I have hip problems, but will be using it on a camp bed, so no worries about cold coming up from underneath.
Probably less of an issue if you're a small child though
We've had various cheaper ones and they were OK(ish).Our son used a Millets own label one quite happily for a few years. Its pack size was pretty big though.
We've all got Thermarest Trail Pros now. Pack smaller, inflate thicker, more comfortable and warmer. Lifetime guarantee too. My feeling is the we should have bought them in the first place but it depends on your finances and whether you think the kids will stick with camping.
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