You said you were getting two SSDs and one big hard drive. You didn't say anything about the cost of the SSDs. But now I know, and yeah, an extra 100 to know you actually have something reliable and presumably with a valid warranty from a legitimate seller or the manufacturer seems worthwhile to me. If it was double or three times as much, I might take the risk with someone like Platinum Micro, but I would rather just go with a drive that is specified as refurbished from a better known seller. At least then you aren't risking being cheated with no recourse (or at least not an easy one) and you know it's someone that does legitimate refurbishing.
serversupply.com is one that we used at my job a lot for getting older drives needed to replace failed drives in client machines (like Dell drives to avoid warnings about uncertified drives). $275 for the same Toshiba drive you got, 90 day returns, 1 year extended warranty available (although by the time you add that you're only 50 away from a new WD Gold). Or less for a WD model which has half the failures of the Toshiba according to BackBlaze (WUH721816ALE6L4 or 0F38462 which are apparently the same physically).
serverpartdeals.com is also one I've seen mentioned as reliable, and they have both of those drives even cheaper (but only the 90 day warranty). They have manufacturer recertified drives as well, although mostly Seagate.