How much and what are you looking for? Silicone, casting resin, rubber? If you are looking for 5 gallon buckets there are different options vs pint bottles...
Smooth On has a great selection and is a great one stop place, but there are a ton of independent or smaller distributors out there offering comparable products at lower prices, but are generally not on stop shop for everything...
If you are looking for small quantities, I suggest this to everyone...
Browse your local paper for Michael's, Jo-Ann, or Hobby Lobby 40-60% off coupons one of those chains almost always has one in the paper, if not Hobby Lobby rotates a 40% of any item on there site for about 3 out of 4 weeks each month...
This week it's a 3d scrap book coupon but it's usually any item, check back Monday...
Weekly In-Store Specials : Hobby Lobby - Hobby Lobby
Take any of the above coupons to your local Hobby Lobby if there is one, they carry a small selection of Alumilite resins and silicones, and with the 40% or more off you can get a great deal on low volume purchases... Hobby Lobby will honor the Michael's or Jo-Ann coupons if you have them...
Yeah only one item at a time but it's easy enough to bring a friend and you each use a coupon or simply walk out to your car, drop it off and go back in for another purchase a little later...
On a last note, not all products are created equal, and price is NOT always the determining factor on quality... The more you play and experiment the more familiar you will get with said products, you might find that the dirt cheap stuff from you local plastics supplier is perfect for one application, while another product works better for a different application...