If you're looking for something to print, take a look here for a community driven 3D repository of everything from artistic jewelry to improvement parts for your 3D printer.
This is a building block style approach to 3D design. Starting with basic geometries and building them in to fantastic shapes or you can design the next best phone case. This a free application.
If we are unable to print your object due to our printer limitations, shapeways is a place that might meet your needs. Shapeways charges for both the amount (volume) of materials used and handling of your print.
If you've done searches on Tinkercad you may have seem articles stating that Tinkercad was no longer being developed and would soon disappear completely. Fear not - Autodesk bought Tinkercad! Read on for details.