Forget the price, buy only quality.
To me, that means Intel or Samsung.
Would I be able to save anything else into the SSD? even if its used as a boot device?
Of course. A 120gb ssd will hold the OS and a handful of games.
It does fill up quickly, and over 90% capacity will start to slow down.
I have been using a single 240gb SSD for a long time with no issues.
If you will be storing large files such as video's or backups, adding a hard drive later is easy.