Yes, I believe the expenditure of money should fall under free speech. Nobody should be able to tell them how to spend their hard earned money. As long as the person is not breaking the aw or doing anything immoral then all should be fine. It's your money, spend it how you want to.
We go to work and earn our money so we should be able to do with whatever we want. If we do not meet our financial obligations, we pay the price for that with bad credit or not having our necessities meet. People need to start taking responsibility with their actions so that our spending would be more in control!
As long as you are not breaking the law, and meeting your financial obligations you should be able to spend the money the way you want. Its almost obvious at this point that money does play a part in speech and you should be able to express your opinion no matter what it is.
If it's your money, you should be able to spend it in any way you wish, providing you're not breaking the law in doing so. For example, you should not be free to buy illegal drug, or child pornography. However, as long as what you're spending your money on is currently legal, the government should not step in and try and stop that expenditure.