Can someone with Computer knowledge explain which would be better to have,a Toshiba tablet or a PC.?

The tablet will be a very easy solution for web access and email. They generally feature a touchscreen and and lightweight and portable. You can easily take them to coffee shops and use free public wireless internet.

PC (personal computer) could be a desktop or a laptop. Laptops can achieve the same goal of the tablet, but generally do not have touchscreens; keyboard and touchpad are their alternative. The laptop and desktop will be more compatible with other devices like printers, webcams, scanners, mp3 players, etc.

I would recommend to you a laptop - lots of versatility, and typically around the same price point as tablets. A decent entry-level laptop should run under $500. Look for Intel Pentium or Intel i3 series with 2GB or more of memory.

If going with a tablet,

make sure to pick up a case for it - broken screens on those are quite expensive to replace.

Depends on what you want out of it. Tablet is portable. Desktop is not. That is the first thing you should answer.