I'm thinking about buying a 30GB SSD for my laptop and want to know if it's possible to install Linux on it via flash drive with nothing else needing to be done. I just don't want to spend the money on it unless I know for sure I can do this.
Provided your computer supports booting from usb, yes you can to an ssd. If haven't booted from usb before you should try before purchasing.
Install unetbootin, create the live-usb, and the reboot the computer and press the appropriate F# key (varies from system to system) to enter either your BIOS, or your quick-boot menu.
If you enter the quick-boot menu, then choose your usb device, and it will try to boot from it.
If you enter the BIOS then you'll need to change your boot order to removable first, save your changes, and then exit the BIOS.
Should be able to fine. I've never installed on laptop but several on desktop.
I've installed 12.04 on several 10GB drives with no problems by booting off of a flash drive to install it. As long as the laptop isn't too old and supports SATA--doesn't require a PATA (IDE) drive it should work fine.