Some of my friends they pray five times but on work they cheat people by charging more money than the real price and make money by doing so. Is it Halaal or Haraam?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

If the buyer willingly agrees to pay more for an article than its market value then the sale is correct and the seller is not to blame for doing so. This is not considered as eating the property of others unjustly. The following Hadeeth proves this. 'Urwah Al-Baariqi reported that the Prophet gave him a Deenaar (a golden currency) and asked him to buy a sheep. Instead, 'Urwah bought two sheep with this single Deenaar, and sold one of the two sheep for one Deenaar and came back with the other sheep and the one Deenaar left. When the Prophet saw him and knew what he had done, he supplicated Allaah to bless him.

'Urwah bought a sheep for half a Deenaar and sold it for one Deenaar, which is twice what he paid for it and the Prophet did not object to what he did. Instead, he supplicated Allaah to bless him. This indicates that selling an article for more than its market value is permissible, but it is not allowed for the seller to cheat the buyer whether this buyer is righteous or an evil-doer. Moreover, the seller should not lie to the buyer when he sells him a specific article.

Allaah Knows best.