I have a macbook pro which I bought with OS X Mavericks preinstalled. I have a Mac Mini with Mountain Lion which I want to upgrade to Mavericks. But since the download size is too big, I wonder if it is possible to create an installation disc or better yet USB using the OS X Mavericks already installed in Macbook Pro and use it to install Mavericks in my Mac Mini?
You can't "install" it, but you can clone an image of the OS on your laptop using Disk Utility and save it to an external hard drive, then restore that image (also with Disk Utility) onto your Mac mini.
Even better, if you can use Target Disk Mode (requires both Macs have either Thunderbolt or FireWire), you can use the same restore feature in Disk Utility to clone directly between the drives without requiring the external media/image file.
This will of course wipe your Mac mini drive in the process and won't give you a clean install. If you're OK with that though, then it might be an option if you really can't afford the download.
Once the OS is installed it can be copied to another system but you will end up with not clean install.
You will have to re download the Mavericks, and save it and do not run the install.
Now you will have a Install package of Mavericks 5.5 Gig.
With it you can create copies and bootable USB.
If downloading is a problem for you go to nearest Apple store and they will do it for you.