But when it turns out she is mistaken, the race is on to get the sold items back.
Ms Walker studied drama in school but never thought of taking it further, and worked in PR after graduating.
But whilst on a two-year overseas experience in London, she started taking acting lessons as a way of meeting new people.
Returning to New Zealand, she threw herself into productions at Rotorua's Little Theatre, including Rattle of a Simple Man and Steel Magnolias.
"I got a huge amount of experience from the Little Theatre, in a really short space of time," she said.
Last February, she enrolled at the esteemed Actor's Program.
Filming for $1 Reserve took place over five days in September, and Ms Walker said the process was truly collaborative.
"It was really intense, but it was amazing ... when we weren't filming, we were rostered on behind the scenes.
"Everyone was helping, from making cups of tea to holding a boom mike ... it gives you an appreciation of what it takes to get the film made."
Series producer Anna Duckworth said the release of the series had been delayed because everyone "is at the beach" over the summer.
But soon Trade Me users will see banners for the series on the website and in the newsletter, which should prove a boost for the series' viewing figures.
And if $1 Reserve proves a success, she might not seem a stranger to the next person she meets through Trade Me.