。
She rents that room out to a student for 70,000 yen a month.
Literal
She [topic-は] that room [object-を] month 70,000-yen [for-で] student [to-に] is-renting.
月 in front of a price reads as 'per month' — short for 月額 ('monthly amount'), acting as an adverbial without a particle. で marks the price (the same で that means 'for' in pricing contexts), while に marks the recipient of the renting. ~ている here describes an ongoing arrangement, not a single past event: she has the room out on a continuing rental. Renting a room to a student is a familiar arrangement in Japan, particularly around major universities — 下宿 ('lodging') culture has a long history, though modern students more often live in dedicated apartments.