Sister is offended that I do not want to lend her money

We had different times in our family, it was like that, without austerity, everything could not be dispensed with. I was sitting in a decree with a small child, and my husband lost his job at that time, but everything went well with time, but the habit of saving was left. But this is not greed, as our relatives believe, who live in permanent debt, namely reasonable savings. My sister's income is almost the same as that of our family, with the difference only that they have two children, and we have one daughter. She never has enough salary until the end of the month, and she immediately goes to me for money, without even calling first, and as it goes without saying that I owe her money. And how, then, will they live to the next paycheck? She somehow decided that this question should disturb me, and not her or her husband.

Every time she comes in new clothes: she liked her boots, could not resist, then someone bought a suit from her friends, and she needed the same for herself. She has a fur coat from natural fur, but when she sees a beautiful jacket, she will never deny herself and buy. When I tell her about this, I hear back: "I do not want to walk in the same boots for 5 years, like you." It turns out that I save money so that my sister can afford to each month a new expensive clothes? She never thinks that if the receipt is paid on time, then you do not have to pay a penalty in the next month. Similarly, with a mobile phone, none of them are interested in the tariff plan, replenish the account when the money runs out. Children are accustomed the same way. As soon as the parents received a salary, each of them immediately needs something: then expensive sneakers, then a new "cool" phone, so that everyone is jealous.

If I say that I can not lend money, I immediately take offense, do not call, complain to my mother that I'm selfish, that I do not help my own sister, but for some reason she keeps silent about the fact that her debts never return on time, or even completely forgets about them. I can not afford to lend money without a guarantee of getting them back and, most importantly, on time. I also have a family, and another thing, if the sister needed, then there would not even be a speech, and I do not want to sponsor her luxurious life.