I have been told the newer 18-55 mm kit lenses are reasonable optical quality these days but have not tried one myself. Don't get the orig 2nd hand version they first made as they were not great.
To be honest unless you strike lucky at a car boot sale or find someone naive selling a lens well under true price you are not going to get a lens worth having at that price - even 'cheap' lenses are dear.
If you are interested in macro photography or close ups you could get some 'close up' lens filters to put on your 50mm or a set of extension tubes which would be a cheap way to get more from the 50mm. You could go wider with a 28mm 2.8 which is fixed focal length and cheapish 2nd hand - I have one I really like. Other than that I would save the money and buy something better later - I speak from experience with this, its easy to waste money on rubbish glass and then wish you had waited longer for something better. Read lots of reviews and understand what you are buying before making a choice - remember that the research and shopping is half the fun!
You could also shop around the Tamron and Sigma lens web sites, many of their kit is reviewing very very well and undercuts Canon for price and you could try these manual focus lenses which seem to be reviewing surprisingly well
Whatever you do, AVOID the 75-300 consumer level lenses from Canon as they are really rubbish and in my opinion the worst lenses in their line up.