If you look at the price history of the Intel Core I7-8700K before and after the Intel Core I7-9700K was released, you'll note that it actually increased in price. People seem to think that just because a newer processor is being release, the older ones are going to go down in price. What they forget is that the higher demand for the older processors causes prices to increase.
I'd be willing to bet you won't see a significant price drop for the Ryzen 5 2600 when the 3000 series chips are released. Personally, I wouldn't bother waiting. If the Ryzen 3xxx series are being released in a month or two, then I'd probably wait for one of those. Otherwise, I'd just get a 2600 as soon as you're ready to.
-Wolf sends