I voted n/n. I have never encountered an online game sufficiently entertaining to entice me to pay a subscription. That said, I swore off computer gaming back in university almost completely, when I found Civilisation II was consuming whole days, so my exposure has been extremely limited. Likewise, I can envisage paying a DM, if there was no other way I could play, and circumstances were such that I couldn't DM myself.
However...
JoeGKushner said:
The only time I can think of paying someone to GM is the following.
1. All characters have miniatures.
2. All monsters have miniatures.
3. All dungeons are using Dwarven Forge products.
4. All city encounters are using models. I forget the name of the company, but there is one.
5. The room is free from odor, cat hair, dust, and spider webs.
7. The room has adequate lighting.
8. The GM provides paper, dice, pens and has a computer archieve of all the character sheets in case a character is lost.
9. Refreshments are served and food is available.
In that case, sure I'd pay.
Perhaps I can add something worhtwhile here.
I play the bagpipes. On occasion, particularly in the summer, I am asked to play at a wedding. Likewise, I am sometimes asked to provide private tuition (sadly, I must turn this down, as I don't have the time

). Anyway, when playing for a wedding, I typically charge £100 (about $200), while for private tuition, I could charge anywhere from £10 to £20 per hour (about $15 to $50).
Now, my set-up costs for playing at a wedding (instruments and uniform) were around £2,000. But that's not really relevant - the customer isn't paying for that. Similarly, I have spent 21 years learning to play, and practice for hours every week to stay sharp. But that's not really relevant either. In order to play at a wedding, I require uniform and bagpipes, and I am required to be good enough. These are simply minimum requirements. What I am being paid for is my time - playing at a wedding dominates the entirety of a day, and costs either a day at the weekend, or requires that I get time off work.
Hypothetically speaking, the set-up costs for private tuition are a lot less. I would require a practice chanter and some music. I would not supply the student with a chanter or (later) bagpipes of their own. I could put them in touch with a supplier, or even order for them, but it would be up to them to get their own instrument. And, of course, if they didn't get one quickly, there wouldn't be any point in lessons, would there?
In terms of expectations, the events are quite different as well. At the wedding, the customer can instruct me when and where to play, and can request specific tunes as desired. If I can't provide this, I let them know, and they can decide what to do. Other than that, they expect a professional service, with me being on time, well-dressed, and competent.
Private tuition, on the other hand, requires that I teach appropriately and well. However, I will inform the customer that it will take about a year of regular tuition from the time they first pick up a chanter before they can play the bagpipes at all well. And that's assuming that they practice in their own time according to the advice I will give them.
So, what does this have to do with professional DMs?
Well, my set-up costs are probably equivalently high. I have a lot of books for d20, Vampire: the Masquerade, and AD&D 2nd Edition. Similarly, I have been DMing for 17 years, and have learned a few things about it. But none of this is really relevant. The customer would not be paying for these things - they would be paying for my time. Indeed, the minimum requirements of DMing for pay are that you have the required books on hand, and are good enough.
I can see a couple of circumstances where someone might pay to play, but they boil down to two cases - special occasions or regular play. For example, if the "old gang" are getting together and want a game to relive old times, but no-one wants to DM, they might hire the services of a pro DM. Or, a group might find that the only one of them who can DM well has had to move away, so they hire a pro to carry on the campaign, rather than pick up the slack themselves. Or, if they're wise, they hire a pro to carry on the campaign, and also to teach them "the tricks of the trade".
In the case of a special occasion, I would expect to show up with absolutely everything required to play. This will typically include copies of the rules for all players (or at least, enough for the group), pregenerated characters, and adventure, dice, and so on. Depending on the game, I might bring a battlemat and counters, or I might not. I would expect the session to dominate a day, and probably cost a weekend day. It would also likely include lots of off-topic conversations, reminiscence, and so forth. In those cases, it is the job of the pro DM to be invisible. If the group get nowhere in the adventure, that's irrelevant. They want to have a good time, and your job is to facilitate this.
A "special event" game would almost certainly be core rules only, with pregenerated characters and a fairly tight script. Special requests could, of course, be discussed (such as the use of 1st Edition rules, the old characters, or whatever).
Regular play games with a pro DM work slightly differently. The DM and the group would have to negotiate ruleset and characters (especially if the game were a continuation of another campaign). House rules would need negotiated, and expectations set. However, in the same way that a professional tutor will not negotiate his teaching techniques, and will generally not negotiate his rate (much), a pro DM is unlikely to accept interference in the internal workings of the game. If you don't like a ruling, find a new DM.
A pro DM in a regular game will almost certainly not supply miniatures and terrain of the manner listed above, nor will he provide the real-world setting of the game. Typically, if the group want to use these things, the group will have to provide them. What you would be paying for is the DMs time.
So, why pay?
The reason people pay for a piper at a wedding, or for private tuition, is that they want the service and can't (or don't want to) provide it themselves. There aren't a lot of pipers out there, even in Scotland, so we're in demand. The reason a group might want to pay for a DM is if they want to play and can't (or don't want to) provide the service themselves. While anyone can DM, running a
good game is an entirely different manner. And it's worth noting that there is a difference between a game run by a newbie and a game run by a DM with years of experience.