[CanadaRAM]

So I need to know:

-It *is* possible to upgrade RAM on my computer, right?

Yes, if it is a CoreDuo first gen MacBook you can go to 2 Gb total RAM with 2 x 1 Gb SODIMMs.
(The Core2Duos introduced compatibility with 2 Gb SODIMMs)

-If so, where can I get this done? Can I just run it over to Future Shop or will it have to be someplace more Apple-friendly?
-How long should I expect it to take?

Well, on general principles I would not go to FS. Any Apple authorized dealer or service centre can do it for you. If you don't want to do it yourself, of course. If you don't have any dealers nearby, then a competent PC shop should be able to.

It's a 5 minute job to install. The main things are getting the right screwdriver to make sure you don't strip the heads of the small Phillips screws, maintaining a static-safe environment while installing, and making sure the modules are correctly oriented and then pushed ALL the way into the socket. It takes a fair amount of pressure from both thumbs to get them to seat into the sockets. There is an initial "thunk" and you think its in, but it's not, they have to be pushed about 2 mm more than the first 'stop'. The number 1 cause of failure is not pushing them in the last 2 mm into the socket.

Here are the instructions
http://manuals.info.apple.com/en/MacBook_13inch_Memory_DIY.pdf

-Most importantly: cost. My friend just got 2 new RAM sticks in his Dell laptop today (both 1024 mb) and it cost him around 140 bucks after tax. If I were going to purchase the same amount, would it be even more expensive just because it has something to do with an Apple product? (Hey, you never know.)

Yes, that is the correct ballpark for price. The RAM does not have to be "Apple" RAM, it does have to be a good quality module of the correct specification. There are a number of dealers and RAM resellers who frequent ehMac who will respond privately with pricing if you wish.

 

[CanadaRAM]

You *can* put 2 x 2GB RAM in that computer, but it will only recognize 3GB of the 4. This is sometimes done rather than putting in 1 + 2 GB RAM, since the MacBook prefers matched pairs.

That is true of the Core2Duo Blackbook, but the OP Said it was a first generation, which would be CoreDuo, and that one cannot take a 2 Gb module.

 

[CanadaRAM]

Minor caveat...a single 2 gig chip will work in a CoreDuo on it's own and show 2 gigs.
Cannot be paired up with anything tho.
MIGHT be a strategy if you have 2x256 to buy a single 2 gig with the idea of getting a Core2 later.

MacDoc - I understood from reading the tests that it had to be a 533 MHz 2 Gb module in order for the machine not to crash -- have you seen it working on a single 667?