At the time of writing a top tier Samsung 960 Evo M.2 NvMe SSD costs $130 for 256GB , while many 240GB-275GB SSDs are found for $70-90 and 480-525GB SSDs are going for $120-130.

There's only a small handful of companies competitive right now:
Samsung (with about half the market ) , Sandisk (about 10% of the market , Western Digital owns them now), Micron (includes Crucial and Intel that is cooperated via IMFT), Lite-on (Plextor , which sources NAND) , Kingston (which sources NAND), and then a large gap in percentage market share before you can mention Toshiba (includes OCZ) , SK Hynix (sort of...)
Samsung is able to hold a large part of the market because they are responsible for the controller and NAND (flash memory) and are extremely diversified (they also have competitive advantage in LCD panels). They can afford to price things lower due to vertical integration and economies of scale.

If you gaze at the Johnny Lucky SSD database http://johnnylucky.org/data-storage/ssd-database.html you will see some trends in memory use and controller use.


240GB:

Sandisk Extreme Pro , leading 10 year warranty , 80TBW endurance rating
---> Marvell 88SS9187 + SanDisk 19nm MLC
---> 480GB has 1GB DRAM instead of 512MB

Corsair Neutron XTi , 160TBW endurance, 5 year warranty *** note that Phison had a USB exploit exhibited at Blackhat
---> Phison PS3110-S10 + NAND Toshiba A19nm MLC
---> 480GB version has 512 MB LPDDR3 instead of 256MB

Corsair Neutron XT , unknown TBW endurance rating, 5 year warranty *** note that Phison had a USB exploit exhibited at Blackhat
---> Phison PS3110-S10 + Toshiba A19nm MLC

PNY CS2211 XLR8 , unknown endurance, 4 year warranty *** note that Phison had a USB exploit exhibited at Blackhat
---> Phison PS3110-S10 + Toshiba 15nm MLC
---> higher sequential write on 480GB version (540 MB/s instead of 470MB/s)

Intel 540s , unknown endurance, 5 year warranty
---> Silicon Motion SM22586 AB + SK Hynix 16nm TLC

Kingston HyperX Savage , 306TB / 1.19 DWPD , 3 year warranty *** note that Phison had a USB exploit exhibited at Blackhat
----> Phison PS3110-S10 + Toshiba A19 MLC
15nm planar TLC (Click to show)
OCZ Trion 150 ... with 60 TBW rating (15nm TLC NAND) , 3 year warranty
---> Toshiba TC58 + Toshiba 15nm TLC
---> 480GB has 54,000 IOPS instead of 43,000 IOPS random write

Kingston SSDNow UV400 ... with 100TBW and 3 year warranty
---> Marvell 88SS1074 + Toshiba 15nm TLC NAND
---> 480GB has 35,000 IOPS instead of 25,000 IOPS for the 240GB

Corsair Force LE , 60TBW , 3 year warranty *** note that Phison had a USB exploit exhibited at Blackhat
---> Phison PS3110-S10 + Toshiba 15nm TLC
---> 480GB version has 512MB DDR3 instead of 256MB DDR3

PNY CS1311 XLR8 , unknown endurance, 3 year warranty *** note that Phison had a USB exploit exhibited at Blackhat
---> Phison PS3110-S10C-12 + Toshiba 15nm TLC

ADATA Premier SP550 , unknown endurance , 3 year warranty
----> Silicon Motion SM2256 + SK Hynix 16nm TLC

Mushkin Triactor , 150TBW endurance , 3 year warranty
----> Silicon Motion SM2256K + SanDisk 15nm TLC
250GB:
Samsung 850 Evo , TLC 3D VNAND with unremarkable 75TBW amount than 500GB capacity that has 150TBW , 5 year warranty
---> Samsung MGX + Samsung 3D V-NAND

Crucial MX200 , 80TBW endurance, 3 year warranty
---> Marvell 88SS9189-BLD2 + Micron 16nm MLC

Samsung 750 Evo, 70TBW 3 year warranty --- don't bother with this , it's not a good when there are cheaper options with better hardware
---> Samsung MGX +Samsung 16nm TLC

SK Hynix SL308 ... TLC Planar NAND with only 75TBW (150TBW on the 500GB) , 3 year warranty
---> SK Hynix SH87820BB + SK Hynix 16nm TLC

Western Digital Blue ... 100TBW essentially a Sandisk X400 product with firmware changes (TLC NAND with LDPC error correction), 3 year warranty
---> Marvell 88SS1074 + SanDisk 15nm TLC

256GB:
Samsung 850 Pro ... with MLC 3D V-NAND , is excessively expensive for what it is , until this hits below $0.35/GB it is not a good buy TBW = 150TB ... leading 10 year warranty
----> Samsung 3 Core MEX + Samsung 3D V-NAND

ADATA SU800 , 200TBW , 3 year warranty
----> Silicon Motion SM2258G AB + Micron 3D TLC

Toshiba OCZ VX500 , (MLC NAND) 148 TBW , 5 year warranty with advanced replacement
----> Toshiba TC358790XBG + Toshiba 15nm MLC

Sandisk X400 , 80TBW (TLC NAND with LDPC error correction) , 5 year warranty
---> Marvell 88SS1074-BSW2 + SanDisk 15nm TLC

Sandisk Z400s , 72 TBW , 3 year warranty
----> Silicon Motion SM2246XT + SanDisk 15nm MLC

Plextor PX-M7V , 3 year warranty 160TBW
---> Marvell 88SS1074B1 + Toshiba 15nm TLC

Kingston SSDNow KC400 , 300TB or 0.65 DWPD , 5 year warranty
---> 8-channel Phison PS3110-S10 controller and 15nm MLC NAND?

Plextor PX-M6V , 3 year warranty
---> Silicon Motion SMI-2246 + Toshiba A15nm MLC

Plextor PX-M6S , 72TBW , 3 year warranty
---> Marvell 88SS9188 + Toshiba 19nm MLC

275GB:
Crucial MX300 ... (TLC 3D NAND) 80TBW and only 3 year warranty, a mediocre deal unlike the higher capacity versions (525/750/1050GB) . All but the the 275GB model have up to 530 / 520 MB/s sequential read/write.
---> Marvell 88SS1074-BSW2 + Micron 3D TLC


Other brands

Patriot Ignite , 3 year warranty
---> Phison PS3110-S10 + Micron 16nm MLC

Transcend SSD370S , 3 year warranty
---> Silicon Motion SM2246EN 4 + Micron 16nm MLC