For the RAM, I would recommend a G.SKill DDR3-1600 8GB set, which should run about 50-60 bucks from Newegg/Amazon. Also, I prefer the Coolermaster HAF 912 to save a few bucks.
For your PSU, it's hard to know what PSU to get from your info. We would need to know what GPU you have in the PC. Judging by you wanting to go economy, an 850 is probably way more than you need so you could save some money probably.
As for SSDs, I would recommend a Samsung 830/840 Pro series. Hope this helps.