Budget noise-isolating earphones/headphones

[creative420]

Every x-mas a friend of mine hands out a gift hamper to his employees. He was thinking of giving away noise-isolating headphone/earphones this time around as they work in a small office set-up and there's metro station construction set to begin nearby. He has a set budget of max Rs. 800 for this, as this will be a part of hamper which will include other gifts.

Thanks in advance.