|Raidmax does not make a great power supply & the specs for the RX-700SS are mediocre at best. I've seen this particular unit for about $75 but personally wouldn't even consider it.|
It's a modular unit which means the cables are can be added or removed as needed. Here's the list of connectors from the above link...the ones you need to be concerned with are in bold:
1 x Main connector (20+4Pin)
1 x 12V (4/8Pin)
6 x peripheral
6 x SATA
2 x PCI-E
2 x Floppy
In other words, you potentially have 12 connections for hard drives and/or CD/DVD drives so there should be plenty of plugs to go around. All these cables *should* have been included.
I don't know why you would need a 700W unit unless you have a high end gaming machine, but my guess is the shop ripped you off.