。
I can't put out that kind of money.
Literal
I [to-は] such money [topic-は] not-able-to-pay-out.
出す ('to put out') in the financial sense means 'to pay, to put up, to contribute.' The negative potential 出せない = 'cannot pay.' The contrastive は after 金 highlights 'that amount specifically' as opposed to lesser amounts. そんな金 ('that kind of money') implies a large or specific sum known from context.