Chunk of change
Chunk of change (English) — Also; a big/large chunk of change. (figurative)
Referring to a significant amount of money, a lot of money. There is no specific amount. This expression is used to magnify the amount that something is value/price. Especially when addressing costs/value of jewelry, homes, cars, services, holidays, (big ticket items).
Change literally is money in coins. A chunk of change when would be a large amount of coinage. Though in reality it refers to large cash amounts.