In the last video in the superhetrodyne series, Chuck Adams (K7QO) goes into the type of solder one should buy. Here is his recommended solder:

Buy a solder with the following breakup of the metals: 62% SN, 36% PB, 2% AG

i.e. 62% Tin, 36% Lead, 2% Silver.

I have never put any thought into the kind of solder I use. I just bought whatever I could find on SP Road, Bangalore (Or Roni Electronics in Kochi). Next time, I am going to see what the constituents of the solder I am buying are.