Trade

Accepting a different currency from a customer and exchanging it for a better rate later on

Q: I work at the airport at a car rental. Now if a customer comes and wants to pay in Euros but we accept only Dinars, to make his work easy I take the Euros from him at the current exchange rate at the airport knowing that the exchange rate will be better outside in the city. So I accept those Euros and use my Dinars to give to the company and later take those Euros and exchange it in the market at a better rate for myself or sometimes I wait for an even better rate. Is this money halaal? 

Getting an item invoiced at a lower price when purchasing from a foreign country to pay less tax

Q: Many people do business and import items from foreign countries. Due to our country charging tax on the items imported, many people get the item invoiced at a lower price in the foreign country so that less tax is paid. I would like to inquire regarding the permissibility and rulings regarding this.

Using freelancer.com website

Q: There is a website called freelancer.com , where a person can hire graphics designers, website designers and the like, to do work for him. One option available is called a contest, where one posts ones requirements and the price he will pay, the money is charged by the website, then various graphics designers who want to offer their services (optionally) create mock ups / designs which the person can then choose between. Sometimes over 50 different designs are made. The person then chooses the one he likes the most. The website transfers the money to that designer, together with taking a small percentage fee for using their platform. The one designer who's design was chosen, will be paid. The remainder who's designs weren't chosen, and had voluntarily posted designs in the hope of winning the contest, get paid nothing. Is this type of contest / ijaarah permissible?