In economics we talk about 'monetary supply' which is the supply of money in the economy (the economy of one country). Monetary supply, is a government policy, and is controlled by selling or buying back government bonds or debt, and also interest rates, credit/lending criteria (tightening/loosening credit rules). So if the government buys back its bonds, or starts to spend more on infrastructure/services, then the supply (the availability) of money in the economy becomes greater: there is more money flowing through to businesses and employees. To supply, is usually used for giving/selling goods and services. "Supply" used for money is only used in economics talk. I think the text quoted is some kind of economics/accounting textbook.

This isn't my area of expertise, but here's my best guess: For sales tax purposes, you are seen as "supplying" something if you give, offer, or provide it to someone else. However, if you give money to someone, you won't be seen as "supplying" it. Specifically, there won't be sales tax on loans. If I give you a loan for you to buy a table, there will be sales tax on the table, but there won't be sales tax on the loan. However, if I give you a loan, and you use the loan to acquire money somewhere else, such as in a foreign exchange transaction, then I will be seen as "supplying" the money, and the loan will be subject to sales tax. Again, I think that's what it means. I'm not completely sure, though--if there are any accountants here, I would be very happy to defer to their expertise. One more note: "help" is not used the same way as 帮。 If I help you explain something, YOU explain it. "My mother explained the math problem to me, and my father helped my mother explain it--he drew pictures to illustrate what my mother said." What you want people to do is help you UNDERSTAND it. You will understand it, and we will explain things so that it is easier for you to understand. Or, you could ask us to help you BY explainING it.

This is really confusing and would do better with context. However, let me try to give you and example. When considering an expedition or military campaign one would use logistics to plan what was necessary. One would need food, clothing, camping equipment. All of these things are supplies. If packages of money were to be brought along to give as gifts or to use as bait or to bury for the future they would be considered supplies to be brought along. When money is used as currency to buy things it would not be considered a supply according to the cited text in your question.