http://store.ricksantorum.com/
I actually got my bumper sticker off of eBay, because when I bought it (last July, I think) the Santorum website didn't yet have such things.
The store at the Rick Santorum website has rally signs, but I don't think that it has yard signs. I bought my yard signs from a site on the internet:
http://www.victorystore.com/rick_santorum/index.php
Their signs seemed to be nicer and cheaper than other places. (Most signs at other places were running $15 to $20 each.) The prices at this place are $9.95 each, 2/$16.00, 5/$35.00, 10/$50.00, 50/$200.00, 100/$375.00.
I started to order ten and put them out around town, but the right of way issues pose a problem. I ordered a couple for my yard. Shipping was $10 (kind of steep, but the total price was better than at other sites).
I bought a couple of signs like this one:
Probably need to hurry. It took about a week for the signs to arrive.