Sources of Income

Doctor charging patients for a sick note if they are not sick

Q: In a GP practice, patients come often for a sick note without being actually sick. Most will say they are tired and need a day or two off. Some practitioners charge for a sick note as a business transaction. 

Is it permissible to rather consult the patient and do a general check up (blood pressure and sugar) and give multi vitamins and then give the note or is it not permissible at all?

Earning via boosting game accounts

Q: I have been earning via boosting game accounts which is basically leveling them up to a certain level and then selling it to customers. However, the game seems to ban some of my accounts because of the violation of terms of sales whenever it detects me boosting them. Furthermore, I'll have to make sure I create as much randomness as possible in the process of making the account so that I cannot be detected boosting them. I would like to know if this is a haraam or a halaal way of earning as I put a lot of time and effort in boosting these accounts and I make sure they are sold to the customers with complete honesty and warranty of the account.

Buying stock from a Muslim who sells lotto tickets

Q: A Muslim shop owner buys stock i.e. cigarettes, cold drink, etc. from another Muslim but the person they are buying stock from is selling lotto tickets or gambling vouchers. The Muslim shop owner wants to know if they buy stock from the other Muslim owner that sells gambling vouchers or lotto tickets, would the stock they buy, as well as the income be halaal or haraam?

Selling ebooks on Amazon

Q: I want to write an ebook and to publish on Amazon Kindle. When somebody buy my book I get paid. Firstly the owners of Amazon are non Muslim so can I sell my book on Amazon Kindle. Secondly when a buyer buys my book I get paid. What if the buyer money is haram and mostly buyers are non-muslim and their money is involved with riba and other haram things. So this type of money will be halaal for me? When someone read my ebook ads are shown on their device sometime but I am paid royalties of my ebook not for ads so this is permissible?

Earning from an item one purchased with haraam money

Q: I used to make money by promoting un-Islamic cartoons. I used that money to buy a laptop. From that laptop I learned and make applications/ programs. Now I get a lot of money from the apps I made. My income now is halaal insha-Allah, but the problem is, my laptop was bought with haraam money.

What is the status of my income now? What about the knowledge I got when using the laptop? Is the money I generated, and the apps I made, all haraam? How do I repent and cleanse my profit/income?