If you want a large screen tablet without the extra cost and don't mind a resistive display or a refurbished model, then the Elonex eTouch could be an interesting option at less than £100 from Cheapest_electrical, a top-rated seller from Ebay.
Similar to the iPad, it has a 10.1-inch display, a chipset running at 1GHz and 256MB RAM. But delve a deeper into the specs and you find that the screen is a resistive one with a 1024x600 pixel resolution and the chipset is an ARM11 model, not based on the more recent Cortex A8.
Other features include Android 2.2 Froyo, 2GB onboard storage with a microSD card slot, Wi-Fi, USB, Ethernet via an optional adaptor but no bluetooth, front or rear cameras or GPS, and the 2100mAh battery is unlikely to last enough for a full day's work (more like three hours).
That said, it's just 25 per cent of the price of an iPad, although it's nearly twice as thick and is fifty per cent heavier. The next step up would possibly be the eTouch 1004ET which comes with a capacitive touchscreen or the Archos 10, both at a higher price.