Getting a good silver certificate value will really take a knowledgeable collector actually seeing the bill. There are so many variables and the market is constantly changing. If you really just want to know a quick and pretty close estimate of the silver certificate value though just find the year "By Series" menu to the right. You will find a list of silver certificates currently for sale and their current price.
To get as close of an estimate as possible you need to find one as to your as possible by paying attention to a few different points. These include the series, the seal, where it was minted, if it is graded, and certainly the condition. Some other information that may help you is below.
1935 and 1957 $1 Silver Certificates
The 1935 Silver Certificate and 1957 Silver Certificates will have a very small premium above their $1 face value. A circulated bill have value of about $1.25 to $1.5 while Uncirculated certificates in decent condition will be around $10 to $20. There are some exceptions to these values, for instance a high graded 1935A Hawaii (Brown Seal) Silver Certificate can easy get over $100. Other higher valued certificates include the Star notes (a small star follows the serial number instead of a letter), the North Africa (Yellow Seal) notes, Experimental notes and numerous rare blocks and range of serial numbers.
1934 and 1953 $5 and $10 Silver Certificates
Here again many of the circulated $5 and $10 Silver Certificates will have only a value slightly above the face value which ranges from about 10% to 30% and the uncirculated certificates, depending on the grade or condition will have a value of around $20-$30. The star notes do have a little bump in value.
There are some rare bills in the series including the the the 1953B $5 Silver Certificate Star Note.
1928 and 1953 Red Seal $1, $2, $5, and $100 Certificates
There is a bit of a spread for value in these bills for instance a typical 1928 Silver Certificate in the $1 denomination can range from $10 to $70. The $2 and $5 Red Seal bills are common enough and will not have a huge value over face value especially if circulated. The $100 Red Seals will have a value around around 20% to 40% even in circulated condition. Of course each denomination and year will have some rare issues.
1923 $1 Silver Certificate
The 1923 Silver Certificate was the last series printed in the large sized or Saddleblanket sized bills. Though they were large there design was still similar to the modern bills. You can find plenty of these certificates under $20 especially circulated. For the graded bills like choice, gem, and 64 they will most likely be over $100 and higher grades can reach over $300.