I actually FOUND this on CraigsList of all places. Someone had posted it in the for sale section. I thought it was a pretty good list of things to look for and questions to ask, so I'm sharing it with you. :]
"What are you looking for in a horse? Are you just looking to pleasure ride, trail ride, rope off of, breed mares, etc etc etc.
If you are a prospective new horse buyer, consider the following checklist. Now these are just general questions to ask yourself. There are so many more things to consider in purchasing a horse, but I tried to come up with something general to go by for those first time newbies. Look at the horse's health first:
Can you see his ribs at all? You should be able to feel his ribs, but not see them.
Does he have rounded pads over his hips or are they pointed because there is no fat on them?
Does the horse have a clean coggins test within the last year? This is to ensure the horse does not carry the equine infectious anemia disease because it is contagious and spread to other horses.
Are his hooves overgrown and cracked, or are they nice and rounded or recently filed?
Will the horse let you touch his legs?
Will the horse stand still while you come up to him?
Does the horse look at you with interest, or does he try to turn his back to you? If a horse has good opinions of humans, it will be interested in you.
Is there a lot of liquid in the horse's nostrils, is it clear or yellow? If yellow, avoid!
Are the horse's eyes clear, or matted up? Do his teeth look healthy, or old and uneven?
If you have a chance to look at his droppings, are they healthy looking in chunks, or runny?
Does the horse have fresh water available?
What kind of feed do they give the horse? A horse should be given free access to good hay, not moldy or black hay, and most of the time, he should be given a supplement of grain unless he's overweight and not being exercised, usually a horse gets two scoops at least once a day. Since horse's have small stomachs, it is best to give them food twice a day and this will keep their weight up better. Do remember, hay is the main staple for the horse, and the grain secondary/additional feed per my vet's advice. He must have hay and fresh water for proper digestion. The amount of food given varies on the horse type you are looking at. A young horse needs more, he burns more energy. A well muscled quarter horse has more body mass and has to sustain the mass with more energy. A pregnant mare or nursing mare needs more energy.
Horses need to be wormed regularly, and there are different types of medicine at feed stores for this. Alternate the different kinds when you do the worming. Like give pyrantel during one worming, and on the next worming about 3 months later, give ivermectin. You can actually get these for a good price on ebay, I get them for 1/2 price there.
Asking more about the horse in general:
Do you need a horse that's papered? If you want to show him, yes. If you want to breed him or her, yes. If you just pleasure ride or trail ride, no. You will usually pay a little more for a papered horse.
Remember, you get what you pay for (usually, anyway). Training and experience in a horse costs a lot, and this will be reflected in their price. If you want a well trained horse that's not too old, you will pay about $1500 to $3000 and up for a horse. If the horse is green broke, this means he has had a saddle on, and possibly ridden a few times but needs more work with reining and leg cues. Always ask about whether the horse has ever bucked or kicked or reared. Hopefully the person will answer truthfully. If they will let you test ride the horse, then he probably doesn't, because it will get found out if the horse tries to buck you off. Can you stay on a bucking horse? Not me!! It wouldn't feel very good to get broken bones which is very likely if you are inexperienced. If you are a beginner rider, I recommend you try to bring someone with you who has had some more experience riding, or a trainer, to help evaluate the horse. After all, for most people, this is a pretty big investment and one that you will live with for up to 30 years or so, depending on the horse.
What height do you need, are you tall or short? A 14H to 15H horse is the average; smaller than 13H or 14H could be considered pony, a 16H to 17H horse is pretty tall. Your feet and legs should be appropriately placed for cueing the horse where it needs to be cued.
What age do you want in a horse? They live to their 20s usually, some can live longer. And it is not good to break the horse before they're at least 2 yrs old, and some should be 2 1/2 yrs old, it depends on their knees. If you start them too early, it could permanently damage their knee joints and their back. I advise waiting to ride until they're 3, but you can at least "start" them, which means groundwork (teaching from the ground) and put a saddle and bridle on them and getting them used to that part first.
What bit does the owner use? Some bits are hard on a horse's mouth, which could mean the horse doesn't want to behave unless he is being controlled by a harsh bit. (high port bit would be harsh). Some horses do just fine with an easy bit like an eggbutt or d-ring snaffle bit and it's not so hard on their mouth. Some horses use a bosal bridle (rope around the nose), which is easy on the horse and most horses like it because it controls them by pulling down on their nose and turns their head with it instead of being in the mouth and therefore doesn't hurt them.
Do you want a gaited horse? This is pretty cool because the gaited horse is much smoother than other horses, especially when trotting. This is good when you are a person with back/neck/physical problems and still like to ride. You will pay a little more for a gaited horse. There are certain breeds that usually gait, but it doesn't always show up in the horse just because of the breed. The only way to know is to watch the horse being worked out. It's like a quick little shuffle walk. There are different gaits, some only gait in front and some do all legs (different beats). You might want to check one out and watch the owner have the horse gait for you. The breeds are Tennessee Walker, Paso Fino, Missouri Fox Trotter, and more. Usually it will be advertised along with the horse.
Well I hope this helps you in determining what you are looking for, and what to watch out for. "