I replaced my HD with a $47 Sandisk 120GB SSD. (FYI: Best Buy does price match so be sure to check online prices before you buy anything. It was $47 online and $80 in store.) They tried to sell me a Samsung SSD for over $100 because their Geek Squad "Googled" that other ones do not work well. I know you get what you pay for, but there was also the option to return it so I chose the cheaper route and I'm very satisfied, so far. (There is also a 3 year warranty.) I had no trouble whatsoever and I'm now updating my OS to El Capitan from the original Snow Leopard that my (mid 2009) MBP came with. I decided to wait on the RAM, battery, etc. As long as it's working I'm happy! Thank you all for your help!
PS: Apparently some people on the web believe you need to keep a dryer sheet in one hand, buy a grounding bracelet, wear an armored suit, and wipe everything down with fabric softener spray to ward of static electricity when changing hardware. A little extreme if you ask me. Honestly, it had me scared to even open the thing up. Yes, it's necessary to take precautions such as not rubbing your feet on the carpet or wearing a wool sweater... but after seeking advice from an IT friend, using a clean work space and making sure to touch something metal to discharge any static will suffice. Just want to throw that out there.
PSS: The dust was ungodly! I'll definitely have to take care of that when I open it back up.
[doublepost=1483636412][/doublepost]Also, to anyone doing this upgrade, make SURE to spend the extra few dollars to buy a T6 torx (star) screwdriver or bit and a tiny Phillips screwdriver (four way, not flat head). That is, if you don't already have those. I only had down to a T10 but luckily, I'm a "handy gal" and had a tiny set of channel locks I used instead of the torx. Having the correct bit would've been better though!