Oregon marijuana shops began selling marijuana Thursday for the first time to recreational users, marking a big day for the budding pot industry.

Some of the more than 250 dispensaries that already offer medical marijuana in Oregon opened their doors soon after midnight — just moments after it became legal to sell to anyone who is at least 21.

At Portland's Shango Premium Cannabis, co-founder Shane McKee says the first sale to an excited customer came a minute after midnight.

Store owners say they're hopeful they can avoid the shortages and price spikes that followed the start of legal sales last year in Washington and Colorado, the only other states where the drug can now be sold for recreational use. Alaska could begin retail sales next year.

Many stores in Oregon were trying to lure customers with extended hours, food giveaways and discounted marijuana.

Shoppers have one more incentive to buy early and often: Under Oregon law, pot purchases will be tax-free until January — a savings of up to 20 percent.

One store was offering a goody bag with T-shirts, but no free marijuana. Another will have a live band and 10 percent discounts. The marijuana review site Leafly will set up with food trucks at a handful of stores, giving away free meals to anyone who promotes the service on social media.

Several stores have erected billboards in Portland. A shop in Merlin is advertising on the radio.

"I'm just trying to basically stock up for maybe four or five times what the normal volume would be," said Chris Byers, owner of River City Dispensary in the southern Oregon town of Merlin.

Customers can buy as much as seven grams at a time of dried marijuana flower and leaf — the part that's generally smoked — plus plants and seeds. For the next year or so, marijuana infused candy, cookies, oils and lotions will be available only to people with medical marijuana cards as the state works on retail regulations involving those products.

Oregon has a robust supply system for marijuana that has supported medical marijuana users and the black market. Companies have invested in massive warehouses in Portland to grow the drug indoors, and southern Oregon has some of the nation's best conditions for outdoor cultivation of marijuana.

Growers don't face strict regulations yet, so the supply can more easily flow into retail stores than it did in Washington and Colorado.

Still, there's concern. Summer has historically been a time of marijuana shortages in Oregon, and most of the outdoor crop isn't ready to harvest. Indoor growers have had minimal time to ramp up production, since lawmakers only approved the Oct. 1 start date three months ago.

"We have kind of a seasonal growing market here in Oregon," said Jeremy Pratt, owner of Nectar Cannabis, which has four stores in Portland. "We have lots of product in the fall, and then it kind of gets tight this time of year anyway."

Green Oasis, which has two locations in Portland and more on the way, has prepared by trying to cultivate strong relationships with growers. On Thursday evening, it will entice customers with a band playing outdoors. People who spend at least $40 on Thursday will get a 10 percent discount, co-owner Matthew Schwimmer said.

"We don't know of anyone else doing a band, and we thought it was a good idea to give back to the community," Schwimmer said.