I have two Solid State disks, both Samsung 850 Pro. (They were leading edge when I bought them, but probably obsolete by now.) I have one in a desktop system and the other in a laptop.
In the laptop, Solid State disks consume less power; hence, generate less heat and extend time between battery charges. If (and it's an important "if," your system has a SATA 3 (or faster) disk interface, you'll see a noticeable speed increase. If your system has an older (slower) SATA 2, a speed increase will be there but you'll need a utility to measure it because it'll be so tiny you won't notice it.
As well, you'll need to configure your system to use AHCI, the newer protocol. Although Solid State drives will work with the older ATA, their full potential won't be reached.
I experimented with a Solid State drive on my "everyday" desktop system, an older machine that uses SATA 2 and ATA. The increase in speed, if any, was impossible to detect.
On my "Power" desktop, which has SATA 3 and is configured to use AHCI, the speed improvement from switching to a Solid State drive was substantial.
A few observations about Solid State drives. . .
In general, they have a huge advantage over magnetic disk drives when reading a large number of small files, especially when they're random. With huge files storing data continuously, magnetic disks avoid the time penalties from mechanical head movement and sector latency; hence, they "close the gap" between the Solid State performance and theirs. My guess is that most users use many small files more often than a few big ones.
When a Windows system boots, a huge number of small files are read. This plays into the Solid State drive's strong corner. It's while booting where you'll notice the biggest speed boost.
Solid State drives work well when they have plenty of unused capacity. The reason for this is that they write data into empty blocks. When empty blocks exist, the writes take place immediately. When they don't, empty blocks must be created. To do this, data must be moved to other locations first. So what happens as the disk fills is that more and more writes require the multi-step process of data movement, block erasing, and finally data writing. Addressing this issue, modern Operating Systems can consolidate partially filled blocks during idle periods, creating empty blocks in anticipation of upcoming write operations. (The need for this "Trim" operation is detected by Windows 10.)
You mentioned cost. I cannot comment on cost.
Hope this helps.
Cheers, PW.
