Online or at the shops. There are many headphone companies that make good headphones such as Audio Technica, Sony, JVC, Philips, Sennheiser, Beyerdynamic, and Panasonic.
One can buy portable headphones at Walmart, Target, Best Buy and Future Shop. It is best to buy good quality portable headphones and one may also find them through Amazon and Ebay.
Ludacris headphones are good but in my opinion greatly overpriced.However if you really want to buy this brand i suggest you have a look on www.currys.co.uk or www.amazon.co.uk/ludacris+headphones.
Buy and Amazonm both sell shadow headphones.
The highest quality headphones you can buy have the finest sound you will ever get from any headphones. Hence the best good quality speakers that you can get into headphones have already been invented - if you've got the money.
One can purchase Motorola S805 headphones online on websites, such as Amazon, eBay and Best Buy. Motorola S805 headphones have good sound and low noise.
Beats by Dre are very good but very expensive, you can buy a fake pair because I have heard that they are actually good as well. Skull candy has some nice in-ear headphones but they stop working after a couple months.
If you buy an iPod, headphones will be supplied with it.
The standard iPod headphones do have pretty good quality, they are called earbuds. You can also buy better ones, which are more expensive, like Dr. Dre brand.
If you are looking to purchase a pair of wireless headphones I would suggest looking into any electronic retail store such as best buy, target or newegg. Amazon carries them as well.
Best Buy.
Buy it. - -"
Amazon is a cheap place to buy Skullcandy Crusher headphones. You can buy a pair for $43.99.