Mediatek promised us a while ago that unlike Samsung with its "Exynos 5 Octa", that has 2 clusters of quad-core CPU's, it will have a chip that has 8 cores, all of them being the same (Cortex A7 at 1.5 Ghz). The question that remains to be answered is if this is any better than having a quad core processor.
For example, I don't think you will notice a difference in how fast most apps load, or even in gaming anytime soon, but you may notice a slight improvement in multi-tasking. So 8-c0re chips, could in theory allow for an Android OS that has a lot more real-time multitasking going on, much like QNX had, without feeling any sluggishness. As it is right now, I don't think the impact on Android will be great, as it already runs great with the latest chips.
In terms of apps taking advantage of 8 cores as you're using them, it may take at least a couple more generations before we even begin to see that in a significant way (more than a few demos). Games could, in theory, take advantage of 8 cores if they are written for them (which most probably won't be until there's a critical mass of 8-core devices on the market). Then there are also apps like camera apps that could use all 8 cores for faster or better processing of high resolution pictures with HDR on or in low-light.
All of this will probably take another 2 or 3 years, if that day even comes, and if most developers don't see 8 cores as just a gimmick they don't need. Right now, true 8 core chips do seem like a gimmick, unless Mediatek can prove to us that's not true - and no, benchmarks won't count - we need real apps utilizing it, and showing significant improvement in performance.
But if you're already convinced 8-core chips are the future, then you can finds this SoC, called Mediatek MT6592, inside the UMI X2S smartphone, along with 2 GB of RAM, a 13MP camera, a 5" Full HD screen, that should sell for RMB 1,499 ($245) to RMB 1,999 ($327), in China.