You want to know where you can buy headphones? Well you can buy them from a number of online retailers including ebay, amazon, even this forums buy/sell/trade section. Physical brick and mortar stores really depend on where you live but generally most big name stores (walmart, target, even gas stations) carry headphones or cheap iems for purchase.
Hope this helped considering you DID ask where you can buy headphones, not what headphones you should buy.
What kind of electric? Just general edm like hardwell, tiesto, alesso? Hardstyle like headhunterz, noisecontrollers, wildstylez? Progress/trance?
I just got beyerdynamic custom one pro earlier this week and love them. Driving them with a e17. This replaces my 900x which has better soundstage and tighter bass. My on ears are has400. Some other over ears- m50, m80, ue6000, lp2
I've had, have or used others. They're all good for electric. My favorite though is the beyer cop. Not because I just got it but because the sq is just awesome IMHO.
I listen to every other than country. Mainly hardstyle and general edm. Usual top40 mainstream stuff and a lot of classical from Vivaldi to Handel.
At $100, probably m50, dj pro100, ue600, lp crossfade