The best option ofcourse is to get the kit from abroad. Will ve cheaper and someone can bring it in their personal luggage for you. Branded wiring is crazy expensive here. I remember I saw the dB link kit at shehryars shop. That kit has a total of 6 meters of 0 awg wire. For 25k, that would have been a good buy. Are you skeptical as to why that kit was for 25k and in the open you found 0 gauge for 8-10k per meter? If that's the case, whoever quoted you those prices were doing their best to rip you off. Some shops demand insane amounts for products they think they can make big profits on
Db link is a Db drive subsidiary. They make some insane audio equipment so their wiring kits are the real deal. Sure they might not be competition level and their total strand count might be a bit lower than say rf, but it'll be miles better than any Chinese 0 gauge wire you get
The cheapest option is welding wire. I've used that before for a Big3. Insane strand count for pennies compared to branded kits but they are not that flexible and a PITA for car audio
