The is one of the best ideas ever to do in Disney!! We did ours 2 yrs. ago. The cost was $25 a tile. You can only put 2 people on a tile. So, this is what we did:
My dh & dd, me & dd, name of vacation and date, FIL & MIL, SIL & BIL! Last yr., we got to see it for the 1st time and it was so cool. My SIL wore red gloves and put her hands around our pics so they would show up in the photo good. My 6yr dd can take her kids one day to WDW and show them the great memories we made @ WDW!! They will mail you a copy of the pic and a quote from Walt Disney and the location of your legacy. I love it!!!