Ritz crackers are a popular pie crust alternative, but saltines are arguably better because they don't have as much butter as Ritz, nor as much sugar as graham crackers.
Cracker crusts use butter to bind the crumbs together, so an already buttery cracker like Ritz will yield an overly buttery crust. The blandness of saltines works better.
Salt is also a natural flavor enhancer, and saltines have the perfect amount to balance out the sweetness in a pie and ultimately make it taste better.
As with graham crackers, run the saltines through a food processor and add melted butter. For best results, use 1 ½ sleeves of saltines (60 crackers) per stick of butter.