Hi! Thanks for playing. The sound effect is a remake of the sonic ring which I took from here: https://samplefocus.com/samples/sonic-ring-type-fx. They have it listed as royalty free under a standard licence. As for why... Well, I thought it was funny to equate a sound most gamers associate with gaining wealth (and life) to the idea of amassing debt, the implication being that wealth itself is a form of debt.