check the prices properly...
they usually come bundled (last time lah... dunno whether they
still practice this)
e.g.
RAM, CPU, m/board very cheap
but you MUST buy casing from them (which will cost a bomb)
usually it's a good idea to get everything from one shop and get
them
to assemble and test that everything compatible with everything
else...
(that's what I do lah...)
saves you time and trips to SL sq (which can be quite frustrating
)