patrick.net

If you have to use SATA: https://www.newegg.com/Product/Product.aspx?Item=N82E16820147373 otherwise if you have a motherboard with M.2. with PCIe lanes: https://www.newegg.com/Product/Product.aspx?Item=9SIA12K54C9642 I didn't try these but they are the reference this day.

I doubt it matters much which SSD you buy, since anything you buy will be way faster than any hard drive.
Also, I love SSD's for the OS and some software, but keep the HD in as well and store your data there, or at least back it up there frequently. I don't trust SSD's for data..

You shouldn't replace an HDD with an SSD if the HDD was doing a lot of writes. SSD's have a shorter write lifespan than HDD's. The best setup is run your OS off an SSD, and your storage remains on an HDD. Check slickdeals.net, they have SSD listings for super cheap almost weekly.

I decided to stay with my current HD. My desktop has an older SATA interface and I would not get the full performance of a SSD if I switched.

I bought a secondhand lappy and PC this year. Quad core, tons of memory, lightning fast SSD. Spent $160 and $180 on them. Look on ebay or check your local storefront computer shops for these kind of bargains.

The speed of the SSD, especially during the boot process, meant no looking back at my older PC.

Come to think of it, my last 3 computers to die, suffered mechanical failure of the HDD.