"inexpensive prices" is correct and usable in written English.
You can use it when referring to the relative affordability of something in comparison to similar items. For example: "This store offers a wide selection of items at inexpensive prices."
Though the restaurant is not inexpensive, prices are fair given the overall quality and stylish presentation of the food.
The grilling is to perfection, the house wine is good and the inexpensive prices will astound you.
The state, which publishes its own laws at relatively inexpensive prices, claimed copyright of the laws' organization and presentation.
When major brands place banner advertisements on the side of a member's home page, they pay inexpensive prices, but the ads receive little attention.
Mimi Neuhaus, who owns Neuhaus Realty and has sold homes in Staten Island since 1969, says the enclave has gradually become a year-round home for people who like its beachfront calm at relatively inexpensive prices.
If Cedar Fair gets a strong summer, the company can make enough money to sell their stock at inexpensive prices.
Inexpensive pricing of gigabit broadband is practical in American cities, too.
Sweetening the victory was the film's relatively inexpensive price; "The Muppets" cost about $45 million to make.
Soon Josiah had even worked out how to print designs on it — all this, at a relatively inexpensive price.
Hideki Matsui and Norihiro Nakamura might come at a relatively inexpensive price, given their eagerness to test themselves here.
But he contended that if an infusion of cash would keep Interfaith open until it could be reconfigured, "that would be a relatively inexpensive price to pay".
