Spot silver value primarily. If you are going to mess around with silver I would suggest you create yourself a link to Coinflation.com. It gives you real time silver value of each denomination silver coin. Just keep in mind that it does not address numismatic value at all. Only precious metal value and that was where you scored on this deal.
First set of pics with the ASE $30, Franklin $10, Merc dime $2 and Standing Lib Quarter $5= $47. Second set with Buffalo Nickels $1-$2 and 2 Roosevelt dimes $4 = $5-$6. Last set with 4 silver quarters( $4.50 ea) =$18. $47+$6=$53, $53+$18=$71. You paid $50 for about $70 worth of silver coins.