A SSD is THE best laptop performance upgrade.
Laptop hard drives are optimized for power savings, not speed. A SSD will absolutely transform your laptop.
I have installed a ssd in every one of my laptops.
Open up your laptop and look at the hard drive. It is simplicity itself to mechanically change it out.
Look to see if you need either a 7mm ssd which is common today, or if you need a 9.5mm thick ssd.
Older intel ssd's had spacers making them 9.5mm tall. You can probably buy or make one if you need to.
Today, I would use Samsung EVO as the best price performer. 128gb is ok, just make certain to not run any risk of filling it up. At 90% capacity it will slow down and lose endurance.
Intel and Samsung offer free clone utilities...