You can't really go wrong with the tiny friends sand
. Some people swear by childrens play sand - others find it dusty and it needs baking to sterilise it. The only two options really are childrens play sand or chinchilla bathing sand (sand not dust).
I was using the tiny friends one but now get this one from Zooplus as it's a bigger 4kg bag. Probably last me a couple of years!
https://www.zooplus.co.uk/shop/small...ter/sand/42425