Just some history. I bought Samsung 850 EVO 500GB for $157.99 in September 9, 2016. I bought Samsung 860 EVO500 GB for $117.99 in July 31, 2018 and now it cost $79.99 (https://www.amazon.com/Samsung-500GB-Internal-MZ-76E500B-AM/dp/B0781Z7Y3S).

It is quite big price drop for few months. Now 1TB cost $147.99  (https://www.amazon.com/Samsung-Inch-Internal-MZ-76E1T0B-AM/dp/B078DPCY3T) and this is less than I spent on 500GB 2 years ago.

And keep in mind that Samsung is one of the leaders of SSD market and if you are planning to buy SSD I recommend Samsung 860 EVO 1TB because it is a bit faster than 500GB. There are not many usages that will require more storage so it should be enough for quite some time specially if you