SOLVE ME

I come in pieces a lot more than two 
Once I was popular now replaced by sadoku 
Some people use me on a big board
I'm never on a computer so no memory is stored

I appeal to all ages both young and old 
Most people play me when the weather is cold
Where am I bought I hear you say 
The answer would be toy shops and e bay

Pieces are put together the task is now done
The humble jigsaw has caused so much enjoyment and fun