So, my DS broke a little over a year ago (almost two, I think), so I bought a DS Lite to replace it. Sometime around July of last year, i noticed my right shoulder button wasn't working properly. I had to apply a lot of force in different areas until i got a response. It usually took about 30 seconds to get a response, which normally isn't too bad, but it's horrible if you're playing Resident Evil. So I used my dieing warranty and had the button fixed for free. All was well and good until the same exact thing started to happen, and my renewed warranty just expired recently. I plan on getting a DSi by next summer, but until then, does anyone have any suggestions? Don't offer any suggestion that requires money, as I have very little of that. Thanks in advance.

Get an original DS. My electric blue DS still has keys that work fine. Either that, or wash your hands before you play.

Sounds like your DS has the classic "Jammy Shoulder Button Syndrome". It's a common symptom that can happen to even the most careful of DS players. My recommended path of action would be to try cleaning the button with a lightly dampened cloth. Then try "exercising" the button by repeatedly clicking it (not too forcefully). Repeat the "exercise" regularly for a few days and see if that helps.

If not, you may just have to wait until next summer when you get your DSi.

is the button going down, but not up, or is it simply not responsive

If it is only sticky: clean it

if not responsive: my brother used a book to tap the button until it began working again. the problem is that nintendo uses a cheap clicker, so it breaks after a certain number of uses (roughly 10,000), and in the ds lite, it is a smaller system, but more fragile. the button probably doesn't work from being used too much, my guess is your resident evil (i had the same problem with meteoroid prime and the firing button) I find that over time the button works again, but shooting games wear out the firing button, so i suggest getting it sent in consistently so that your warranty doesn't die, and it keeps your system in smooth running.

for the time being try shifting the button around gently to try and see if it isn't lined up properly. the button you are clicking is about the size of this -----> O (the edge of the outer ring)
know this because I have broken my ds lite multiple times in the shoulders (cracked the right shoulder off 3 times, and broken the locking part 2 times) and I am fairly careful with my ds, i just use it too much... I sent my ds in twice a yar even if it didn't need it, just to keep the warranty, but then i went for 3/4 a year I thought... turns out it expired the week before I called it in, sonow I have a ds that is hanging from the wiring in the hinge, and it costs $90 to fix... so I'm rather ticked with nintendo... they couldn't used stronger pieces that cost less than a dollar more?

sorry for the rambling, and i hope my advice helps