I’m looking to get the Denafrips ares 2 cheaper.
They don’t show up used very often, and usually at not much of a discount, use Hifi Shark, it searches most of the common sites.
The only other real place to look is AV Exchange on Reddit.
head fi, avExchange and the buy/sell thread here should serve you well. Possibly ebay from time to time
go to hifishark make an account and then search “denafrips Ares”, save the search and then you will get emails when new secondhand listing pop up in there database.
They show up on the used market semi regularly here lately, but usually for not much less than the msrp and sometimes more.
Saw one for sale on head-fi