Lot's of people swear by the Toddy Cold Brew System, but cold brew really doesn't need to be expensive or complicated. If you have a grinder, a big enough jar/container, and a way to filter it, that's all you need.

Personally, I do an 8:1 water to coffee ratio in a mason jar for 12 hours on the counter, or 24 hours in the refrigerator, whichever fits my schedule better. Then I filter it through my AeroPress. If you're looking to invest in equipment, look into a quality Burr Grinder like the the Barratza Encore