Hiya....
Dont know if this helps mate, but I buy loads of my steel for fabrication from the frag yard...just call in and ask if you can have a look when they have lunch break...one of my local ones lets me buy what I like at just over scrap price and you get some really good stuff as loads of engineering companies just frag their offcuts....
I bought what must be a good three 8x4 sheets worth of 4mm steel plate, in 6"x 4foot strips....for a fiver! Not only is it loads cheaper but I would sooner buy like this as far more managable than huge sheets of steel...
Just a thought anyway...might be worth a try local to you...
Hope this helps
Gregster