Is it a good time or bad time to buy RAM
Also how much would I have saved by buying it earlier last year?
Not really. A quick check of Crucial.com reveals that a 256MB stick of PC2100 will hurt your wallet to the tune of $75. In answer to your second question, I picked up two sticks of the same memory for $62 back in October. That said, you may have to wait a little while for memory prices to drop. The memory makers got killed in Q3 and part of Q4 last year. They aren't going to lower prices without a fight.