What MWP0004 said. We need to know:
-- If you're planning to build a brand-new system from scratch, planning to upgrade to a new system & reuse what you can (SSD/HDD, DVD-ROM, etc.), or just need a new CPU for your current system
-- If you want a complete brand-new build or the major upgrade, we need to know your budget
-- If you just need a new CPU for your motherboard, we need to know your current motherboard model & your budget.
For example, the i3-6100 is comparitively cheap (http://www.tomshardware.com/reviews/best-cpus,3986.html, shows running for ~ $120 USD)...but if you don't have a Skylake-based system already, you'll be spending more for a new motherboard & RAM (as it would be preferable to go with DDR4, which so far only...