NUC: Gigabyte BXBT 2807 (199)
RAM: Crucial DDR3 1333 (10600) SODIMM (Notebook/Laptop RAM) (4GB) (50)
SSD: Plextor M6S 128GB (109)
OS: Windows 7 Home Prem (125)
Total cost: $483
Buy at Laser Distributor, #05-58. DIY yourself. If you can't into DIY, bring the parts to PC Care & Solutions, #02-32, and ask Nigel to assemble for you for a fee.
Notes:
1) A Celeron N2807 CPU in the BXBT 2807 is more than enough for office work, net surfing and DL/Streaming movies.
2) The SSD is completely optional, but installing a SSD will allow you to enjoy much reduced boot and load times and enable you to enjoy a much responsive system.
3) The BXBT 2807 is very small and compact (About the size of a jewellery box). However, due to its small size, it can only contain 1X 2.5'' HDD/SSD. If you want to expand storage, consider buying an external HDD or if you do not want a SSD, get a Hitachi 1TB 7200 RPM 2.5'' HDD for $87.
4) Got Mastercard? Buy the SSD at lazada.com on a Monday and get 10% discounts when you pay with a Mastercard. Do note that discounts are capped at $50.