I found a local shop which sells refurbished and recertified HDDs for a really good price. Some are refurbished, some are recertified, it’s not both at the same time.
Do you have any experience with them? The shop gives a standard one year warranty with them.
I’ve used plenty of them with no problems for years. Just so long as you have redundancy in place like a good RAID setup there’s little risk of losing anything.