Your asking for an iPad competitors , but want it cheaper than the iPad?
Right now most of the real competitors are priced close to the iPad, but they do offer more features than the iPad, like Front Facing Cameras, RAM, disk space.
The cheaper tablets are cheaper because they don't have the same quality hardware.
It looks like you are also exploring getting a 2yr contract if so you can pick up the Galaxy Tab for $399. This comes with WI-FI and 3G. At the moment this is the considered the only real compeditor to the iPad. Personally I belive the hardware on the Galaxy Tab is better and you have Android 2.2 + Flash with this device. The device is designed for a business users so it intergrates well with calendars, note taking plus their media spin.
The next closes is the Viewsonic 10" G tablet it goes for $399 (
link) it is WI-FI only so it will not contain the market on it. See the review for more info (
link)
There is also the Velocity Micro Cruz 7" Tablet T103 priced around $299.
The trap is not to weigh the price on screen size. The hardware beneath the hood is also important.
At the end of the day however the only two tablets that have any real substance is the GTab and the iPad.
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