What are some other sources are you looking for? There’s no standardized API schema for fetching price so it’s not as easy as just swapping a new one in. There’s custom code that needs to be written for each source. Happy to add more. 

 I mean choose the price manually. Sometimes I would like to calculate how much satoshis I would get if I buy 100 dollars with bitcoin price of 40k. 

 Oh, I can add that.