"The ban is freaking everyone out because everyone is smoking it," she said.
"People aren't going to be able to pay their rent as they're going to buy as much as they can.
"I've got two bags and that would normally last me two weeks.
"You don't tell an alcoholic you're going to take alcohol away in two weeks and then just do it."
She said she had smoked marijuana but in the past five months had used the synthetic products to get her off it. Now she had an addiction to those.
"The law's not right. They bring it out and then they see shops are making a bit of money and they're not liking it. People aren't getting locked up because they're not smoking marijuana. People are addicted to it now and I reckon there'll be a bit of trouble.
"I never thought I'd give that [marijuana] up but it's helped me do that. I'm addicted but I can just stop."
One customer said he had bought his "lucky last" and hoped he could wean himself off it.
Another said the ban "won't bother me at all".
Rachel Broughton said she didn't like the ban.
"I'm for [synthetics]," she said. "I don't know about stocking up but I'll get a couple of bags. You always get idiots who spoil it for everyone else."
Skingraft owner David Young said some customers had been buying slightly more than normal, such as five bags instead of three. Anything left over would be sent back to the manufacturer today.
"We're hoping we'll get a refund."
At least one retailer was handing out information on what to do if users had difficulty detoxing.
