I see businesses put pallets out for free all the time. They tend to be a combination of both hard and soft wood, so can either be separated or if you burn a lot, burn it all and do a chimney cleaning in the summer. The tools are cheap enough and you can do it yourself, if you can get to the top of the chimney without killing yourself.
What are you burning the wood in? If it's a fireplace, you're wasting your time and sending heat right out of the chimney, actually increasing your heating bill. An insert would be better but of course you have to traipse crap across your interior space. Same for a wood stove in a living area. Better is a wood stove in an unfinished basement and best (in my opinion) is a wood furnace in the basement, connected into a forced hot air system.
I do the last thing on that list. I forest manage my property, giving me $1000 or so in tax relief every year and with free wood (save for the gas/oil/chainsaws/repairs to chainsaws/tractor maintenance), adding my own labor to the mix, I keep the house heated. Got it up and running before heading out to work this morning.
I would be very careful about having some clown dump a bunch of green pine on your lawn. Even if you can mix it in with your hard wood, pine is going to take about 5 years to really season enough to use it. If it's a huge pine, like 25 inches in diameter, good luck with that....it's junk. I take crap like that, load it on my trailer and bring it to our recycling center where they take junk branches and leaves. Well, not 25 inches in diameter, but the garbage soft wood branches.
I really would call the guy back and make sure it isn't soft wood.