A great microphone I can recommend that is within your price range would be the Samsung Go Mic. It has fairly good quality for being around the price it is and I actually considered buying it at one time but decided to spend a little extra money.
Samsung Go Mic: http://www.amazon.co.uk/Samson-Mic-Clip-USB-Microphone/dp/B001R76D42/
Sound Test: http://youtu.be/-vHaXgDRO_w?t=2m27s
However if you are willing to spend a little more or to wait to get some extra cash the Samson Meteor USB Microphone is also a good choice.
Samson Meteor USB Microphone: http://www.amazon.co.uk/SAMSON-METEOR-Samson-Meteor-Microphone/dp/B004MF39YS/
Sound Test: http://www.youtube.com/watch?v=ZGQ4kJVAv1E
Good luck on your hunt for a microphone.