You know, I never noticed her hand. I looked at the figure with the a magnifier- it's OK. The figures were made by a European Company- they are more relaxed, but not quite that relaxed..
To try and answer a bunch of questions:
I use Sketchup, netfab, the netfab cloud service, Meshlab and then finalize in Blender. They are all free, and although there is a learning curve (that I'm still climbing), I am getting starting to get the hang of it.
Generally I design full size in sketchup, then use netfab to scale the item (multiply real world by .0115 to get to HO), then meshlab centers the object (which I don't really understand- I just know I have to do it). Blender is a very capable 3D CAD program but I only use about 5% of it's capabilities. I use it to add some details that I designed in separate parts, and to duplicate when I want multiple copies of a particular item, and make the sprues that I connect the different pieces together with. If it sounds kinda complicated, it was, but it is getting second nature at this point. There may be better ways to do things than my way, but I found a way that works.
As to using Sketchup, which is a fairly simple program overall, there are many online tutorials. And Shapeways.com has a wealth of good tutorials, too. I have customized sketchup with add ons- there are many that add extra functions not found in the base program, and quite a community online devoted to the program. There are also many, many models designed by others online. I spent quite awhile looking at other's work and trying to see how they did things, When you design for 3d printing there are differences, however. For one thing you want models that are hollow whenever possible, becasue printing is based upon volume of material used. A hollow model generally costs a lot less than a solid one.
The cheaper plastic is limited to a wall thickness minimum of 3 scale inches in HO. The more expensive to 1 scale inch. Wires, a term for something that sticks out on it's own like a roof vent pipe, has to be about 3.5 scale inches in HO. That is something you have to keep in mind when designing.
I don't even know how much the printers shapeways use cost. I can't afford my own, and the technology is advancing so fast I wouldn't buy one right now anyway. I did that with a color scanner when they were new- $1200 for a scanner that had to go over the picture 3 times and took minutes per scan- at 300 DPI. I cried when I sent it to recycling.
I suspect there are other producers beyond shapeways. That is something I plan on investigating in the near future, For instance, I designed a rolltop desk and chair that I really like:
But a closer look at the chair revels a mistake I made in my design which casued one of the back supports not to print:
After I fixed it, shapeways says they can't print it because the spindles are too thin. Kind of frustrating.
As to purchase, there are many products in the model railroading section of the shapeways website which can be purchased. Shapeways prints and ships the design. A designer can mark up the price if they choose and make a profit. There are some civil war era products that are astounding and put my efforts to shame. And it makes products available to segments of the hobby that are too small to support traditionally manufactured products.
Costs vary, and there is a flat $6 shipping charge per order. As I would guess there is a policy about advertising on the forums I won't be any more specific, but visiting the Shapeways site is entertaining, even if you are not interested in making any purchases. It is somewhat buyer beware, though, There are many designers that put products up for sale without making a test print and using a computer render to advertise them. The final product may not live up to the computer rendering, or may not be printable at all. And, even if it has successfully test printed, Shapeways may say it won't print when you order it. It is a frustration that can occur.
I've rambled long enough. I am an average scratch builder, but working with 3D printing I can design something beyond my skills with an exacto and glue, but get the same satisfaction. It's certainly not for everyone, but that is what's grat about this hobby- there is room for a lot of different people with a lot of different interests and we all seem to fit together somehow. Now I have to go put New Haven Railroad decals on my Spectrum undecorated 2-6-6-2 to give some rivet counter fits :)