"How much did you spend?"
Chinese doesn't have tense though. I'd want to hear a native Chinese speaker weigh in.
I recently learned from Chinese pod on YouTube that something like 你花了... The 了 indicates an action completed. Not past tense.
Completed or changed. Many languages don't have a concept of "tense" but instead a different one of "aspect". But most English speakers don't know the second term unless they've studied linguistics or a foreign language and tend to overuse the term "tense" to cover all kinds of changing verb endings in all languages.
了 can be used with actions in the present or future and actions in the past no not always have to use 了.