Board prices range from $150 a month to $2,500 a month, so no one can judge whether your prices are right. As far as cost for the horse, that's just subjective. If you feel he's worth that much, he his.
I can tell you what I've spent on my horse in the last 6 months to give you an idea of what I have to budget for. Of course, depending on your region, these prices could be higher or lower.
1. Vet bills: pre-purchase exam $150 (1 time). Teeth floating: $100 (every 6-12 months). Worming $20 (few times a year). She hasn't had any health issues, but that's where the real money comes in. I would put away about $1500 for random health issues, but this could be way under budget for some horses and/or regions.
2. Farrier: my horse is barefoot, but she had to be trimmed often because we work on soft ground. Here it's very hard to find a barefoot trimmer, so I pay about $85 per trim, once per month or so, to a person who travels a long distance to get to me. That's more than most people pay.
3. Tack: I've probably spent $3,000 on tack, but that's mostly because I love to shop for that stuff. I have a few saddles, lots of bridles, different bits, and so on. You could probably spend $1,000 and have everything you need, especially if you buy second hand.
4. Treats, etc.: I buy treats and shampoos and fly sprays and so on every month. I'd guess I spend about $50 a month on that stuff. You don't have to buy any of this if you don't want to. I enjoy it.
With regard to whether a 6 year old is too young, I have watched these boards for a while and also seen things happening at the barn where I am. The general consensus is that 6 is too young. Generally speaking, you're better off with an older horse who is more experienced and more patient and more calm when a beginner is on his back.
I bought a 12 year old and am very happy with her. She's very calm by nature, but at this point she's been ridden on trails, at a school, been through Parelli training ... she's seen and done a lot, so not a lot freaks her out, even me bouncing around on her back off balance (poor girl). I almost bought a 5 year old, though, and the only thing that kept me from doing that was we discovered navicular problems during a vet check. He was wonderful. Calm, respectful, well trained. So even though I'm telling you to buy an older horse, I was ready to not do that myself. :) Sometimes a certain horse just grabs you and it seems very right. If this horse had been without the navicular, he would be in my barn right now.
Regardless of what horse you choose, I recommend you have an experienced rider on him/her at least every couple weeks to put the horse through its paces. A horse will quickly lose it's tuning with a beginner on it all the time. The better rider will keep the horse doing well with proper cues and so on.
I notice after I have my expert on my mare's back, my mare works better with me in the lessons after. She becomes the teacher, once she remembers what it is she's supposed to be doing. Sometimes my cues are totally off and my balance is crap and she gets confused. The better rider reminds her that the old/good cues are still the ones she should be paying attention to and she calms right down into teaching mode with me.
With an older horse, you get a lot more of the horse teaching you, which is really handy. If you have one that's too young, it's both of you learning at the same time which can be frustrating and then the bad behavior comes out.
The pricing list was extremely helpful thank you! A lot of it is a lot more reasonably priced than I was anticipating to be honest lol. Board around here is usually between 150-300 depending. I like this particular barn because it includes feeding and watering, the gelding wouldn't be lonely has there are other horses on the property and he has 80 acres of trails to ride, that's crazy impressive only 20 minutes from my downtown city residence heh. "My" gelding isn't shod either but the BO has a barefoot farrier that comes out regularly and is 40/horse, which I found very reasonable.
Honestly I would prefer a much older horse. 13-15 WOULD be ideal... But 1. You can't help who you love hehe he's not the most beautiful horse but I LOVE his disposition and personality. But MUCH MORE IMPORTANTLY 2. I am limited in my options. I have severe allergies and this horse is the only curly for sale in my area that's reasonably priced for his training. Plus the fact that I've known him for 4 years, seen him ridden multiple times, seen him tied and groomed in different situations (out in a busy paddock, in a barn during a thunderstorm) and he was the calmest horse there. I have been able to test on him in person and know I don't react to him.
For broader information, there is a second curly breeder in my province. They have WAY less experience breeding and they are (imo) far too overpriced. Here's a break down between the two stables:
My stable: 2008 born calm, broke to ride bakshir curly gelding, starting over jumps - 6500
The other breeder: 2012 born bakshir curly gelding, halter broken - 6500.
It's a little obscene to me.
Please don't get me wrong, I'm not going to be a blind green rider and buy him tomorrow just because he's available. Since the lady I would be buying from is also my trainer (and she has refused to sell him in the past because she didn't think the fit was right) I'm confident she won't even humor me if it isn't a good match. She's knows I'm very interested in him but we've never discused it because I know I'm too green to bring it up. I will trust her judgement for when ever it is that I'm "qualified" to ride him for the first time :)