I am confused in choosing which arduino to buy?
I've given the three links below
Help me to figure the differences between them!
Lilypad ATMEGA328p ebay1
Lilypad ATMEGA328p ebay 2
Lilypad ATMEGA328p amazon
They look to be the same thing.
.
The two cheap ones are clones - notice the slightly different silkscreen ("JP3" visible next to the ICSP header). AFAICT they are identical in capability.
The more expensive one will definitely work (assuming it's actually genuine, not just a better-looking clone), the two cheaper ones will probably work fine.