Has anyone bought a Swiss Pass in Switzerland? Can you purchase them from any Swiss train station?

Yes you can, but currently they are cheaper if bought in the US thru RailEurope - why i don't know but check www.sbb.ch - Swiss Rail web site with pass prices bought in Switzerland and then compare with RailEurope - i've checked several times and about 10-15% cheaper here than there - same exact pass. For US prices call Re or their agents (800-441-2387) - price differential varies with exchange rate of course. But be sure you can purchase them at Swiss train stations if need be.

When you buy them in the U.S., can you also get the family add=on that allows under 16 year olds to go free?

How much less expensive are they if you factor in shipping/handling etc.? J.

BETS (800-441-9413) charges no handling fee for orders $250 and over that don't need express mail - so there are not fees - Raileurope i think charges $15. Yes in US thru RE or agents you get the free Swiss Family Pass for kids 15 and under - kids must travel with a parent no other adults qualify, like grandparents. I always recommend BETS because of their expertise - i've bought passes from them for years and they are Swiss train experts. You could also consider the Swiss Card and Swiss Transfer ticket, also sold by RailEurope and agents at prices less than in Switzerland.