I think you're looking in the wrong place. A 1TB Samsung 860 SATA drive is under $150 on Amazon. The solid state drives (ssd) are more expensive than hard disk drives (hdd) but they're soooo much faster. I gave you a pointer to one in an earlier post and Roy gave a link in his post.
They design those laptops to be serviced, and those that have multiple disk drives often have simple ways of getting to the drive slot. If you can do electrician work and woodwork, you can put a disk drive into a laptop. Go to Acer's website and see if you can find the hardware maintenance manual for your laptop. They give step-by-step instructions in those manuals for how to do things like installing a disk drive.
Mike
Here's some instructions for a computer which may be close to yours.
I also found some YouTube videos but I don't know if they address your specific model.