Travelers heading out for a long trip from Denver International Airport have lost their cheapest parking option.

The airport last month eliminated its flat fee of $48 for 30 days of parking at its 61st and Peña lot.

Long-term parkers now pay the lot’s standard daily rate of $6, which would add up to $180 for a 30-day stay — nearly quadruple the price.

DIA spokeswoman Alex Renteria said an average of 485 vehicles per month took advantage of the rate last year.

“During busy times of the year — holidays, spring break, summer vacation — the lot fills frequently,” she said in an email. “… Since this lot is first-come, first-served, (we) cannot guarantee parking availability in the lot. There were customers who purchased 30-day parking but were not always able to find a spot to park.”

61st and Peña was the only lot managed by the airport that allowed 30-day parking for a flat fee. Drivers can park at any DIA parking lot for 30 days and pay the daily rate for that lot, Renteria said.

The daily rate at the 61st and Peña lot, which opened in 2017, previously was $4, but it increased to $6 in August, along with rates at a number of other airport lots. It remains the airport’s cheapest lot. The lot is not served by a shuttle but is located along the commuter rail line that serves the airport.

Guests looking to park for 30 days for a flat fee still have several options off airport property, although none approach $48.

USAirport Parking advertises monthly rates of $139 and $278 for covered and uncovered parking, respectively, while Fine Airport Parking advertises $275 to $375 per month. Corporate long-term parking is also available through Canopy Airport Parking and The Parking Spot, although the companies don’t list rates online.

Fort Collins-based startup Stow It, meanwhile, began working with off-airport lot Park DIA in December to fill vacant parking spots with customers looking for long-term parking for a minimum of 30 days. Right now, Stow It is working to fill 400 vacant spots at the lot, said Carmelo Mannino, CEO and co-founder.

Mannino said 30-day parking through Stow It at Park DIA costs $91 for an outdoor space and $215 for a covered space. Park DIA allows vehicles to park for longer than 30 days, but drivers pay a daily rate starting at $7.45.