Amazon is price matching Computer Alliance but you can also purchase from Computer Alliance's eBay store and take advantage of the PLUSITUP coupon code saving you another $20. The eBay store also has the $100 cashback promo as part of their image so it should be OK. I had a quick skim of the T&Cs and while they say "authorised and participating ASUS retailer/reseller", they don't specify any (that I can see).
OK. The rules for cashback are a little weird but I believe this promo is basically promoting loyalty. You need to already own a product from Table 1, then purchase a product from Table 2 within the promo period. If you purchase the RT-AX89X, you can get $100 cashback.
EVENT TIME
2023/04/01~2023/05/31
Example Scenarios:
You are eligible for the cashback promotion with any purchase of one or more of the routers in table 2, as long as you already purchased or own one of the participating routers in table 1.
E.g.
Scenario 1: You have purchased 1 x RT-AX88U in 2023, and you have purchased 1 x RT-AX86U in 2023, this means you are eligible for $50 cashback
Scenario 2: You have purchased 1 x RT-AX53U back in 2019, now in 2023 you have purchased 1 x ROG Rapture GT-AXE 16000, this means you are eligible for $100 cashback
Scenario 3: You have purchased 1 x ZenWiFi XD6 in 2023, but you do not already own an eligible router from Table 1, you are ineligible for the $50 cashback
Lol that wifi router kinda looks like Blood Gulch