£100 would certainly get you started with something pretty decent. You want a 'standard' kite with a good wind range and ready to fly a few to look at might be -
HQ Maestro 2 - Nice big kite, easy to fly, does pretty much all the tricks and comes with a decent set of lines. Most of the frame is 6mm carbon so cheap and easy repair if you break it ( I have one and haven't managed to yet).
https://www.youtube.com/watch?v=s2cqTGiNzrg me messing around with mine.
Also Prism Hypnotist - Another big kite made for beginners and comes with lines and a DVD - will do most tricks, a bit on the heavy side but a nice kite.
https://www.youtube.com/watch?v=vBHivxhI-0YFor something different the Spiderkites Zodarion is slightly smaller but still a great starter kite. All 6mm carbon so cheap to fix.
http://vimeo.com/3258307And of course you can get secondhand kites come up in the sales section of this site.
Whether to get something like a Benson yet depends on what you want to spend - if you did get one and later find you didn't like it you would get most of your money back if you sold it but if you break it then repairs are a bit more expensive ( they are pretty tough though).
Maestro & Hypnotist from
http://www.kiteworld.co.ukZodarion from EmKay kites -
http://www.kites4you.co.uk/contents/en-uk/d62.html