As somebody who uses painting services regularly due to time and also the fact I can afford it some general points for you to consider;
1). I pay about 20 dollars per figure on average AU per standard rank and file.
2). I pay about 30 dollars per figure on average AU per character figure.
3). I pay about 40-50 dollars per figure on average AU per special character
4). I pay about 90-100 dollars and above for anything like a custom job on a Raider or something else.
The quality i expect is well above table top standard on standard figures. I expect a decent job on base colors and shading at least with one color and a wash and a decent basing job done on my rank and file figures.
The issue becomes however is your point of difference.
You won't beat Ebay china painters or India on price, and the Quality level out of China is now moving steadily upward.... in fact I got myself a single DE assassin figure as an auction for less than 10 bucks and its easily superior tournament quality.
Where the point of difference for Euro and American painters is that they can capitilize on is the affluent market. Your not going to make thousands from school kids and the like or even uni students... they don't have the cash.
What you want is the market that wants to do single figures at high quality as centre pieces for peoples armies. Something that you can charge upward of 60 bucks or 30-40 pounds for a single figure done to specific schemes and then planned out with the client.
If you want repeat business;
1). Be there for the client, answer emails promptly
2). Give a realistic time frame and actually show you want the commission. Things like oh I am going away with my job or whatever immediately say to me, fine this is a hobby for you, not where my money is coming from.
3). Ensure you keep them informed every step of the way and make sure you understand exactly what they want done and how it is to be done.
Most people are wary of using the China mobs and India mobs as they dont understand 40k well enough to paint accordingly... A mate of mine had a space marine figures done in a specific chapter only by a well known painting service that charged about 10 bucks a figure.... the figures were great.... shame that they put devestator weapons on commanders..... armed predators incorrectly, armed dreadnoughts with whatever they saw fit.... etc. They just dont understand 40k well enough to do it right as they are painting in a production line. They also have the issue of... hmmm half my army looks like a good painter did it, but those others look like crap that the new boy starting last week did.
If you are up front, give them a template about left arm this weapon... right arm this weapon.... squad leaders to have so and so shoulder pads.... sgts to have a banner.... where you want tactical markings..... or even simple stuff like ok you want a squad of terminators, 1 with chainfist and assualt cannon, all others to be storm bolter and power fist, sgt to have banner and closed helmet with power sword. Painted in Ultramarines color scheme as per SM codex page..... Then you are already ahead of most of the market for being a reliable painter and you will attract the market you want... older, professional, larger disposable income.
In the last 12 months I have paid out about 3k in painting AU dollars wise.
If you want three services to model yourself after;
Nocturnal Studios here in Australia are the best customer service I have ever had. From phone calls on day of when my figures arrived through to follow up phone calls and emails to ensure that everything was painted according to specific instructions. (300 figures painted for me and I have just placed a 800 dollar order for FW raw product then they can paint it for me). I was SUPER PEDANTIC with what I wanted done. I wanted Codex chapter markings done on all my squads and specific armaments and poses and even down to what backpack I wanted on squad leaders.... they did it all like it was nothing new and did it perfectly.
The polish group minaturepainters.com are great quality, but their customer service is a bit slow. Takes a few days to get back to me and always blows out on time by 1 to 2 weeks for a project. (50 odd figures painted for me)
Ibis Minatures in the UK. Painted my entire Dark Elf army within 6 weeks for about 1.5k AU. Professional, fast, superior painting easily superior tournament standard for a 2.5k points DE army. They pruchased the figures as well from GW. Joe and Andy are the real deal for proffessionalism and service. Longest I waited for an email response to a question or clarification was 6hrs. (And I am in OZ and they are in the UK).
Hope this gives you some insight... There are plenty of people like me out there who are dying to get figures done... the problem we face is getting them done timely and done correctly according to what we want... you capture that market, you will win and could have an incredibly profitable business. Nocturnal Studios just charged me 200 bucks for a single dreadnought from FW to paint it.... do I know thats expensive? yes.... would it be at evy metal quality done exactly as I want? yep.... so i don't care. 200 bucks for a single dread for the game I have been playing as my major hobby since 87... that will sit in a display case in my games room? yes please.... in fact... here take more cash thanks as long as I could say.... thanks that looks like Dave Taylor painted it for a Codex and you got the number on the dreadnought correct, the chapter markings, the pose and the custom banner done perfectly that shows the pilot pre internment. Thats what some of us are more than happy to pay...