2,5” SATA SSDs - still a valid option
The m.2 format may be growing, but most over-the-counter SSDs are still in a 2.5" box. It is noteworthy that the 120GB segment appears to be virtually extinct. We were able to find two more available SSDs in this limited capacity, but besides the size, the performance also doesn't make you very happy.
Fortunately, from about 80 dollars you can get a 250GB model, which we consider to be the minimum capacity of an SSD in the year 2018. The performance appears to vary considerably, but one of the models with the most interesting price-performance ratio is the Samsung 860 Evo 250GB. The extra cost in this segment is less than in the higher capacities, while the overall performance is good.
The sweet spot in terms of price per gigabyte seems to be 500 GB at the moment. With this capacity you can easily install your operating system and all other software without getting into trouble. Crucial puts a very good price on this segment: at the time of writing, you can get your MX500 500GB home for an average of 90 dollars, and with a good search it even comes at less than 90 dollars.
When the new 860 Evo models were introduced, they were considerably more expensive, but they have now fallen sharply in price. You still pay a little more than for the MX500, but the Evo's are just a little faster and a little more economical.
Now that prices are falling again, it is becoming increasingly attractive to go one step up. Crucial also priced the MX500 aggressively in the 1TB segment, but WD's 3D-nand SSD can also be called affordable. Crucial, however, wins in terms of performance and is therefore the better buy.