The only coins that contain silver is the quarters, dimes and halves. The total silver content in a 5 quarter set is 0.9042 troy ounces and in a 10 piece set the silver content is 1.3382 troy ounces.
Derek, The silver proof sets are a throwback to the pre-1965 era when dimes, quarters and halves were 90% silver. Coin composition information like this is readily available in a Red Book. If you don't have a Red Book you should buy one.
Other than the 1999 and 2001 years, the Silver proof State quarters go for around $4 to $10 each, many times including free shipping on eBay. Always pick the sellers with the highest positive feedback rating and acceptable return policy! Steve