It can be valued quite well depending on what platform you decide to sell them on - try ebay
Depends on the record you hold , condition , release details . For pricing you need to check in with a local store personally
Depends on the artist and song's fame.
That totally depends on certain factors including how old it is, its overall condition etc
Price also varies depending on these factors and it also depends on the person!
Age of the record,overall scarcity,sealed records,condition of the record,withdrawn releases