Hi guys,

Need some speaker help here.

Loooking for a 6 speaker sound system and receiver that can play music at a low volume in our store.

Requirements are that:

speakers be small.

6 can play in different areas of the store. Not in "surround" mode or whatever you call it as the music from a single speaker will be what the customer hears when they're in the store.

Price under $500, preferably under $300

Wired, I have access to ceilings and existing system to replace so that will be simple.

Receiver that lets me manually adjust volume on each speaker.

Are there any recommendations?

no expert, but probably some sort of sound system--like from guitar center, PA thingy with several channels.
tied to a cheapo home receiver

Orb Audio sells what you want but they're just outside your price range ($600 vs $500).  Perhaps you can find some used Orb satellites.  I like mine and they are unobtrusive in the extreme.  

This should work for the distribution part: 4-Channel A/B Speaker Selector w/ Volume Control

4 Pack Ceiling Tile Speakers - $200
JBL 8138 - 4 Pack

70 / 100 V amplifier w multiple inputs
JBL CSMA 180 Amplifier - $450

Over budget by a bit..