Larry Parker walked into Lowe’s the other day to buy a sheet of OSB plywood for a home project.

“When I put the OSB in my cart it was $26.95,” Parker said.

By the time he got to the checkout, Parker says the price on the store’s digital signboard had changed.

“It ended up being $33.50, which is [over $6] higher,” Parker said.

Welcome to 2021’s lumber price insanity, where the price of a two-by-four can jump in minutes, due to a nationwide lumber shortage.

Fortune Magazine says lumber is up over 200% this year. A chart, in the video above, shows costs for builders and rehabbers are soaring.

“It was $400 a year ago, and now it’s up to $1,200 — so it’s three times the cost,” said Brad Olinger, president of Sterling Homes.

Olinger can’t give buyers an exact quote anymore.

“We give an estimate of what the price will be, and then we bid everything out,” Olinger said.

And it’s not just lumber going up in price: Almost all home-building products, including plumbing, drywall — and even drywall paste — are a lot more expensive than they were in 2020.

Marc Michaelson is the owner of Michaelson Homes.

“It’s incredible,” Michaelson said. “We’re seeing shortages in plumbing materials, electric materials, drywall — drywall has doubled in the last year.”

Blame a perfect storm of pent-up demand, along with last summer’s lumber yard shutdowns caused by the coronavirus pandemic.

It’s all added $24,000 to the cost of a $300,000 home, according to Business Insider.

Experts are hoping prices — and the craziness — ease in fall 2021.

For those planning a home project, try to lock in the price or scale it back a bit.