as another poster already pointed out, most brands are certified by the UIAA the stuff to look for: ropes (EN 892:+A1:2016) in Europe carabiners/express sets:

as another poster already pointed out, most brands are certified by the UIAA the stuff to look for: ropes (EN 892:+A1:2016) in Europe carabiners/express sets: EN 12275: 2013, UIAA 121: 2018 "schlingen" (don't know the english word) for express sets: EN 566: 2017 belay devices: DIN EN 15151-1 , DIN EN 15151-2 (UIAA standard) if you're in europe and want to buy a bit cheaper try decathlon, they have decent stuff from their inhouse brand "simond" and everything is certified and safe. Otherwise.. just by from a decent brand, the stuff is safety critical.. so I personally would not cut cost with the gear :)