Honestly, if it were all sterling you are looking at $1000's in value. Old saying, "if it's too good to be true then it's not".
Maybe there are some sterling pieces mixed in but I would look for pieces marked sterling and stay away from EPNS, nickel silver.
There are certain makers whose silver plate has some value. Especially, old English Sheffield Plate but you need to know the hallmarks. Another that has scrap value is silver on copper for its copper scrap weight.