Shoestring (lazo) you may know. Here the focus is on idioms (modismos) that use “shoestring”. Examine these:

Mr. Boris Johnson, the British Prime Minister, runs his office on a shoestring. This means that his office operates with little money.

Mr. Podemos, a Spanish Vice President, says that he lives on a shoestring (…vive muy justo). It means that he has little money to live on, or his budget is tight.