no tablet can replace a laptop.
newegg often has sales on 'em, but you can find random sales on 'em and will during summer from guys like best buy, staples, office max, and office depot as we get more 'back to school' stuff. hell, the websites of the manufacturers can often find a deal (e.g., right now HP allows you to build a computer for 600 that has the latest and best chip in the family i'm about to mention).
if you want cheap and good and photoshop isn't something you do, then look for something where the processor is an A6 or A8 out there as many of them are currently going from 300-400 because the newer generation of that chipset is out and priced a bit higher (peaks at around 700 right now, HP has some offerings at $600). you'll be able to game a bit on 'em too (if an A8, quite a bit) as they combined a good GPU with the CPU to get where they're at.
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"Maybe it's a tentacle, molesting the planet itself. - Aschen Brodel.