Thanks a lot guys for your replies. Below are my replies to your queries.

The expiry dates are : 2002 for the provia, sensia is 2009 and the elite chrome is 2006. the 400tx is not expired and i opened a plastic can to see inside (was curious). Should i store the 400tx in a fridge ? the thing is that the fridge is pretty cool, almost freezing (sometimes freezes eggs), and the room and outside tempearture are around 20-22 degrees C here in Bangalore at the moment, and it's not so humid as it rains less than in other regions.

For the prices I got them at the following prices:
Sensia was 110 rupees / 1.4 euros / 1.83 USD / 1.21 GBP - per roll
Provia was 150 rupees / 1.90 euros / 2.50 USD / 1.65 GBP - per roll
Elite chrome was 175 rupees / 2.23 euros / 2.93 USD / 1.93 GBP - per roll

He still has a lot of sensia and a few provia, do you think it was a good deal and I should go there again a pickup all the other rolls ? I haven't found someone to do E6 process in Bangalore but I found someone recommend by many people offline and online in Ahmedabad that can process E6 for 200 rupees per roll and great quality processing, would you think it is crazy if I get 10 more slide rolls ? 200 rupees is like 2.5 euros per roll ! In europe it would be like 20 euros per roll to develop it.

Can you get prints from slide films like with negative films ?

@thuggins : you think I should keep those two rolls in the fridge then ? It's just that its a very very cool fridge, I wouldn't want to brutalize the film or something (it sometimes freezes eggs ...).

@TheFlyingCamera: what do you mean with a half stop or full stop, i'm still struggling with that definition. My camera is all manual. I have a shutter speed wheel with 1,2,4,8,15,30,60,125,250,500,1000,2000 on it. You recommend overexposing right ? Should I do it when taking the picture or with push or pull processing when I send it to the guy ?

Thanks again a lot guys ! Sorry for all the dumb questions it's just that I learning analog photography here in India and I'm lucky enough to be in a country where this hobby is much cheaper than in europe so I want to learn the most I can and shoot the most I can ^^