If you want to avoid the $20 fee and don't mind a bit of technical work, follow the steps commonly shared in subreddits like r/aseprite and r/PixelArt. Prerequisites
Compiling requires about 10 GB of disk space due to the necessary developer tools: aseprite compiled download reddit
On Reddit, you may find people offering pre-compiled .exe or .dmg files for download. Be cautious: If you want to avoid the $20 fee