eBay for RAM, should be pretty cheap for used stuff. Also, drive caddies eBay or Amazon, there are companies that make clones that work just as well as the originals. HP wants you to buy their drives, which were really just rebadged drives at 5-6 times the price. I'm assuming this is a SAS machine, if you want new drives you can use SATA drives in a SAS controller (can't go the other way) and it will work just fine for a home server. If you are fine with used, SAS drives are on eBay for pretty cheap.
eBay for RAM, should be pretty cheap for used stuff. Also, drive caddies eBay or Amazon, there are companies that make clones that work just as well as the originals. HP wants you to buy their drives, which were really just rebadged drives at 5-6 times the price. I'm assuming this is a SAS machine, if you want new drives you can use SATA drives in a SAS controller (can't go the other way) and it will work just fine for a home server. If you are fine with used, SAS drives are on eBay for pretty cheap.