For a 4 dollar plant, I think putting it in the ground now is worth the risk! I would protect it though when temps go below 20F just so that way you dont get too much damage, but it should do okay. For some reason the sabal minor I got at Lowes received damage in the low 20sF and Im not sure if Wal-mart also sells very tender cold hardy palms, but if they do, protection would definitely help it out. The reason why I say plant it now is because I dont think that its worth fighting the aphids, spidermites, and all the other pests that it get indoors. But you can easily keep it indoors without too many problems. Keep it outside until December and take it back out in mid march. It would only spend 3 months indoors which isnt too terrible and you can always take it out on warm days, or leave it out if your having a nice mild week!
Good luck and great find, dont you love seeing cheap, nice plants!
-Alex

I'm not any of the above listed members, but in my opinion (I grow in-ground tropicals in Michigan), I would plant it now. If it gets some damage, it will regrow, unless they sold you a sabal palmetto. I just planted a 5 gallon trachy the other day, which I don't plan to protect. I planted it as an experimental palm, with the trunk literally a foot from the house, and roots about 6" away from the foundation, on the south side of my brick house, surrounded with dark red lava rock, under an overhang, and with a wall that blocks winds from the east as well. This is the best spot I have on my property to plant a palm, so it will be as dry and as warm as possible without active protection. We will see if it makes it, but yours is a hardier palm and you're a zone warmer than I am, so I say go for it.

can def plant it now even tho the air temps drop in a zone 7 in november... doesn't mean the ground temps match the air, they never do... your palm will first start to establish its roots once grown, then the fronds/ crown. so if the air is cold and ground is warmer it will def try to focus on the roots getting established which is most important for the palm. and a zone 7 in nc isnt much for a sabal minor as being in the top 2-3 for cold hardiness... so i would easily plant it now. hope it helps -Justin in VB

can def plant it now even tho the air temps drop in a zone 7 in november... doesn't mean the ground temps match the air, they never do... your palm will first start to establish its roots once grown, then the fronds/ crown. so if the air is cold and ground is warmer it will def try to focus on the roots getting established which is most important for the palm. and a zone 7 in nc isnt much for a sabal minor as being in the top 2-3 for cold hardiness... so i would easily plant it now. hope it helps -Justin in VB

I would plant it-Sabals don't do to good inside.

Make sure you protect the leaves,they can be VERY slow
to recover,some Sabals will only grow a leaf or two in a season.

My S.Louisiana grow 5-7.