Grandstream phones work well and are fairly cheap.  I don't know about the newer ones but the older ones (Budget Tone/GX2000 series) weren't as nice (tinny call quality) as Polycom/Astra/Cisco phones - expecially the Polycom/Aastra HD voice phones (HUGE noticeable difference in sound quality).  They work just fine though and if you've never heard the difference you wouldn't know (think VCR vs DVD).

JD