That really sounds like a good deal, nowadays. I'd take it.
Of course after checking over some things, like :
-daily routine/extra care (feed and water times and how many per day; in warm weather are extra water sources provided or is the water checked more often)
-On the feeding: is every horse treated the same. If you provide the supplements, will they feed it, is salt or mineral provided?
Requirements(like mandatory halters on all outside horses. Some with good reason like it, some with good reason, do not;
-Emergency Calls/notification(when they call the vet, and if they will do it with or without owner consent. Common sense stuff; when they call the owner if something happens; so on and so forth)
-location from my residence
-the condition of the other horses BOARDED
-condition of the fences and enclosures/paddocks
-ask to see the hay, if it is not in plain sight.
You will need to check and see about thier leniency if you fall in a bind and may be late with a payment. If you are late with a bill is your horse going pay for it in lack of care.
You need to really have a several thousand dollar emergency vet fund for those "Just in Case" moments. Unless you are doing monthly vet checks on your horse or have a vet bill payment, a monthly vet bill is unknown.
Your initial vet check of the horse will determine how much/when dental will be needed.
Shoes are choice, but really if you aren't doing "much" with him, like showing, or riding often over rough terrain, or need correctional/medicinal shoes, they are just another thing with nails to get lost in the pasture.
You will need to ask how often the farrier comes out and how much "thier guy" charges for footwork, like trimming, and then get him on a schedule.
You may need grooming supplies. I know boarding barns who supply grooming tools for all residents, and others who offer an x amount of space in the tack room for your own tack trunk and supplies.
It is common courtesy to supply a halter anywhere. Don't take him off the trailer, turn him out in his area, and put the halter back in the trailer. If it is a larger facility with several different boarders, buy a personalized halter so it will deter thieves. Of course leather is "better", for the reason it will break if your horse gets in a bind, and nylon will not, except for the breakaway halters and them, not always. I ADORE Valhoma brand halters. The one I have has enough holes on the crown that I can put it on my horse who has a head like a saddle-trunk, and then turn around and put it securely on my hackney pony without fear of it slipping over his nose. I love it.