$540 via promo credit when you add a new smartphone line with your own 4G/5G smartphone on postpaid Unlimited Plus plan between 5/18/23 - 5/31/23 & port-in req'd. Promo credit applied over 36 months; promo credits end if eligibility requirements are no longer met.
You can get from ebay or craigslist, as long as its a fios MI424WR or the quantum gateway.
You can get any Fios router from ebay or craigslist, the above and also the old westell's and older models of the actiontec. They will all support your network speed hardwired though the older ones will only be wireless g - you can circumvent that if it's an issue by adding your own wap in the network.