Med.7z -

Unlike WinRAR or WinZip, 7-Zip is completely free for both personal and commercial use and never "nags" for payment.

Set the Compression Level to "Ultra" and use the LZMA2 method. MED.7z

If you're using it to archive data, here are some optimal settings recommended by the community: Unlike WinRAR or WinZip, 7-Zip is completely free