My SSR's arrived from an eBay purchase last week.  I got a set of 4 10A / 120V solid state relays for about $24 including shipping.  Not a great price, but reasonable enough.  I was in a hurry to get this done.  I haven't tried the SSRs yet, but at least now I'm ready to start my own holiday lighting project.   Let the obnoxious blinking begin!

Note:  if I had a digital camera I'd take a picture and show you what these things look like.  The panel mount types are easier to work with, in my humble opinion, for the uninitiated with these types of electronics.