Costly day in court for Denise Richards … a judge just ordered her to shell out $5,000 a month to her estranged husband, Aaron Phypers … but she claims she simply can’t afford it.

Denise was in court Monday when a judge ruled she must pay Aaron temporary spousal support as their nasty divorce drags on. The judge also ordered Denise to cough up another $30,000 in attorney’s fees.

When the order came in, Denise reportedly muttered … “I can’t afford it” … according to The California Post.

When Aaron filed for divorce back in July, he said he had no income and wanted spousal support from Denise, estimating she was grossing over $250,000 a month from OnlyFans, brand deals, TV gigs, and appearances.

Denise was seeking spousal support from Aaron … but in the end, the judge ordered the money to come out of her pocket, not his.