In reply to BusyLizzie:
I use monthly contact lenses made out of silicon hydrogel and cost me £18 a month. They are simply amazing, can't feel them in, you can sleep in them and it's pretty much like viewing life in HD. My optician said some people wear them continuously for the whole month, I got to 4days then got a bit freaked out - but they still felt fine!
The only downside is you can't really swim with them in, as there is a risk of getting an eye infection, but I have daily disposables for this.
I personally find with daily disposables you get dry achy eyes after about 8hours or so, but with monthlies as they are much better quality I never have this problem.
Another added bonus is they have UV filters, so I don't actually have to wear sun glasses as my eyes are protected!
Avoid any cheap lenses like 'daysoft' they're cheap but wreck your eyes