I sent my mare to a AQHA trainer/judge for 30 days and it was $600. Was it worth it..nope she came back worse then when she left...but not saying all trainers are like that of course. I guess it also depends on what you are wanting your horse trained to do.
I have never used a professional trainer but my Dad used to be one. It really depends on where you live and how many trainers are around that area. Just a few years ago, Dad would charge $450 a month for feed and training, now he charges $650 to $700 a month and his horses are generally ready to go and almost as broke as they can get within a month or 2. However, I have a friend in Amarillo that sent his gelding to a trainer for 30 days and paid $1000 just to get a horse back that had never been out of the roundpen, wouldn't stop, and wouldn't turn....................... go figure. The trainer told them "Ride him in the round pen for another 30 days before you take him out" and it took all of about 3 rides for the horse to start bucking my friends wife off (she is a better rider than he is). So he asked that I go out and ride him a couple of times. Boy, does he need a new trainer that will ride the piss out of him every day for about 3 months. He lays on the bit, doesn't give at all, is sluggish to cues, and when I got on him, he had no cue for forward movement, zero stop, pulls against the bit when you tighten one rein and ask for the turn, and had a real bad habit of veering the other way.
Sorry, that story has no real purpose except to show that you need to be careful where you send a horse.
I definitely agree that being selective with a trainer is necessary.
I am thinking of taking AZ to the instructor/trainer that my husband takes lessons through. I see her, her husband, and her daughter all working with horses every time I go watch one of his lessons, and her training program (spelled programme cause she's from Europe and I ♥ her) seems really thorough. Plus, she allows for stopping by anytime, and even watching them work whenever. They even let you know when they plan to work with your horse if you ask them so you can come see how he/she is coming along.
It's $400 a month and is a 2-3 month program. Seems reasonable. She also combines a LOT of methods, rather than focusing on just one person's way of doing things.
My 3 year old has had 6 months of training at $600 per month. For just $3600... he does english and western. He still does not have the best lope but he's coming along really well. He fractured his pelvis as a yearling so we were careful not to push him real hard on collecting into a slow lope but it seems he's fine although he will never crawl like some western horses do.
I had a halter horse in training and it was $400 per month... but that was just for me because I had worked there forever. Everybody else paid $600. I am sure that it has gone up by now though... I had horses there for about 6 years.
I would see my horses every day in the summer not too mention all the odd hours that I ran on weekends when I was in college. I would never want to have my horse somewhere that didn't welcome me visiting anytime. That just seems suspicious to me.