Gandhi First Day Cover

Do we have any stamp collectors here? I found a box of first day covers in my garage, two of which are Gandhi first day covers, which look like they came from India. Would anyone know how much they are worth?
Scan below

Take a look and see when it came out. It's usually worth ½ to a store and about ¾ to a collector. My dad was a collector and I have boxes of covers, plate blocks, sheets, of stamps US only.
I did it for a while with him but lost interest.

THanks Radarman - I'll let you know how I do.

Please do, it sounds interesting. I should sell them all, I could buy a few super computers.

I don't know if they list FD covers in Scotts Catalogue (stamp bible). Stop at a book store and look it up.

Mahatma Gandhi...What a great Man!!!

(Dear moderators if you think that is a politic position of me and is overulled fell free to delete it).