LEWISTON – At Val’s Drive-In, things have changed a lot over the past 50 years.

Root beer, once 5 or 10 cents, now costs $1.35. Frosted plastic mugs have replaced glass mugs for ice cream floats. And along with the traditional hamburger-and-soda fare, customers can now get fried Oreos.

But one thing has remained exactly the same at the Gregoire family business: The cash register ringing up all that food.

“I love that sound,” said Gail Gregoire-Lawrence as the old register dinged with a sale. “My father’s eyes used to light up whenever he heard the sound.”

John Wheeler built the Sabattus Street A & W Root Beer drive-in in 1959. When Val Gregoire bought the place in 1974, he changed its name to Val’s Drive-in. His daughter, Gail, bought the tiny restaurant from him in 1995, and her son, Chris Lawrence, bought it from her last year.

The National Cash Register Company machine – with its wide body, thick buttons and clanging drawer – has been there since the drive-in opened in 1959.

“They made things to last back then,” Gregoire-Lawrence said.

They also made things less expensive. In 1959, a family could get a whole meal for a couple of dollars. Because of that, the cash register’s buttons only go up to $5.

Prices in 2007 are another story. A couple of weeks ago, a carhop rang up a bill for $75. She had to punch the $5 button 15 times.

Sales tax can be tricky, too. Carhops have to use a modern calculator to figure it out.

“I know we could get a more technologically correct cash register, but this one fits here,” Gregoire-Lawrence said.

The drive-in prides itself on its 1950s and 1960s feel, with carhops (in poodle skirts on the weekends) and Motown music piped through speakers. The old cash register was part of that. So when the grayish brown machine needed some sprucing up, Gregoire-Lawrence painted it bright red. When a drawer panel became loose, Chris screwed it back on.

The family recently considered getting a second one just like it to ring up ice cream, which they recently added to the menu. But Chris was startled by what he saw on eBay.

“I found the cheapest one around $1,600, $1,700,” he said.

Customers had offered to buy the cash register before, but the family had no idea it was actually worth anything.

No matter what it’s worth, the family won’t sell. The cash register’s been ringing up sales for 50 years, they said, and it could ring for 50 more.

“This is the easiest thing there is,” Gail said. “We just take it for granted.”