We own Frigo Returns and bought it from Ebay. If you want to play Pokemon hacks on a GBA then I'd suggest getting a slot 2 flashcard thats capable of playing extended roms, like the Supercard. However, it shouldn't be too difficult to find an emulator without getting a virus. Try going to the original website, or sourceforge, and remembering to look for any checkboxes during install that will give you junky toolbars.
EDIT: also, carts of Pokemon hacks are usually really... bad. They fall apart quickly, sometimes don't compile correctly, and are often completely unfinished, and sometimes really bad hacks. Realize that most of these were made in about 2005-2007, when the Advance games were still new and ignorant parents would buy the "cheaper" alternative after not realizing that it was a fake.