The first gen Ryzen chips do better with 3000+ speed RAM where 3200mhz seemed to be the sweet spot. The new 2nd gen 2600 is less picky about RAM speed and offers better gaming performance, so you may want to consider spending the money and getting the 2600 if possible. Regardless of what you pick make sure you buy RAM in dual channel, so for 8gb buy the kind sold as a pair of 4gb stick, 16 a pair for 8gb etc.
One last thing, if this is your first build dont buy a cheap PSU, get something like a 550 watt sicne you have a 980ti and they can be power hungry. Budget wise Corsair CX and CXM (the ones with white and black lettering, not green) are pretty good and same with Seasonic S12II and M12II (they are sold at 520 watt which would be enough)
Also save your money on the cooler, get something like the Crorig H7, people get fairly moderate overclocks off the stock AMD cooler so you don't need massive expensive cooler unless for whatever reason you want one.