Step 1: Getting Your 3D Model Ready for Printing
First you are going to need to prep you model that you are going to print. If you downloaded something (as apposed to making it with a software like Google sketchup) then check if in the file type is .stl, if it is, you can skip this step.
If you are using Google sketchup, then you are going to need to get an additional plug in that let's you export your model as an .stl file. But, what you need to do is export your model as a .stl file.
For sketchup, you are going to need to download this plug in (it's made by google) which can be found here. Then go to file>export stl and name it then hit export.
Now you should have a 3D model in a .stl format and your ready to move on to the next step.
Step 3: Featured Print (optional)
If you don't have a file to print, you can also check out the featured print page on the website, it has a list of featured prints that are pre-priced, and already uploaded.
Step 4: Getting Your Settings
Now you are going to need to set up the settings, choose your print precision, .4 being the least precise, and .1 being the most precise.
Note: the better the precision you choose, the higher the price will be.
Then pick the amount of objects that you want to print. You can print 1 to 5 prints for each time.
I picked the default settings which is .3 precision and 1 print.
Step 5: Finishing Your Order
Now, on the page that comes next, click the finish link. This will bring you into an email form that you need to either paste or attach your .stl file to the email and send it. If it is to big then there is another page that you can go to to put your file. It can be found on the FAQ page (there's probably another place that it is but I didn't look for it). Then just send the email. You should get an email within 48 hours (or so it says) I got a reply email within about 10-15 min. Which was faster than I expected.
Step 6: Paying
Next you are going to need to pay your fee after you get your quote email. You can pay it via PayPal. It will give you more details about it on the website. As a side note: the shipping is a flat rate of $5.75 for two day shipping, unfortunately for a lot of people though, it is currently only available for shipping in the USA.
The price of my print was $6.00 + shipping, compared to $31.95 for the same print on shapeways.
Step 7: The Print
Here are some pictures of my print which was printed at .3 mm precision, overall, I'm very happy with my print.
Be sure to look for another Instructable using my 3D printed iPhone for prototyping. I also printed a 3d model of the moto x 1st gen
Step 8: Final Thoughts
Unfortunately right now I don't have a 3d printer yet, I have a lot of cool ideas that I could do with a 3d printer, but I don't have the money to buy a 3D printer, or use flexbuild 3d all of the time. I have entered this into the 3d design contest and formlabs contest in hopes to win and be able to create more cool projects that include 3D printing, so, if you want me to publish more cool 3d printing projects, please vote for me in all of the contests that this is in.
Also, I am going to make an Instructable soon with the iPhone 5s model that is shown as the object that I 3d printed using flexbuild, so look for that in the near future.
Update: I have made an instrucatable with the 3d printed dummy phone. You can find it here.