Computer Hardware Discount - What entry level computer can I buy for cheap to later replace HDD and RAM?

What entry level computer can I buy for cheap to later replace HDD and RAM?

I want to buy a cheap computer (like 300-600$) and then replace the RAM to 8GB and change the Hard Drive into a 1TB hard drive.

The cheapest, easiest way to accomplish what you want is to build it yourself. Be careful to get a motherboard that will support the upgrade.
Give me a few days and I will have nice computers with flat panel monitors for under $200. I buy at auctions, fix them if needed, sell them and help out those who can't pay out $600-900 for a good PC email me @ steve@diespy.com for more details
consider refurbished units from Tiger, and Tiger sell 1 tb hds for 149 that are sata. ram is cheap too. You can get a refurbished one cheaper than you can get parts and build one from scratch