Since it says "The internal battery has died, time related events will no longer occur" when i start the game, is there any way i can get the sale items? Either by a gameshark code to force the sale or codes to buy the items at any store?
Short answer: No.
Long answer: Not unless you want to learn how to make your own gameshark codes, which involves some pretty heavy stuff. Nothing that you can just jump into. To get an idea of what goes into a gameshark code, you can check out this lovely page from stackexchange
. There are no simple how-to guides with step-by-step instructions on how to do this.
Helpful answer: Just get an emulator that supports emulating a RTC (real-time clock) for games like Emerald. VBA for Windows and Mac OS X, as well as MyBoy for Android support this.
Don't emulate unless you own both the game and the console. Otherwise you're being a colossal jerkwad and are the reason we can't have nice things.