Best way to get cheap set ups is to go second hand. A lot of people buy a tank then fail at cycling, lose all their fish and give up. You can get some very good bargains, if you search around in your area.
I'll second fluttermouths suggestion. I've picked up a few great tanks for mates upgrading, last was a 130ltr for 70 quid. Check out eBay locally, gumtree even Facebook.