For continued use beyond the trial, you can purchase a license directly from the official Acute Systems Buy Page : $59.00 USD.
Developed by Acute Systems, TransMac lets Windows users: Transmac Serial Key
A Transmac Serial Key is a unique 25-character code used to activate the TransMac software. The key is required to unlock the full features of the software, including reading and writing Mac files, accessing HFS and HFS+ formatted disks, and burning CDs and DVDs. For continued use beyond the trial, you can
Create, compress, and expand Apple disk images (.dmg, .dmgpart, .sparsebundle, and .sparseimage). For continued use beyond the trial
TransMac, developed by Acute Systems , is a Windows utility used to read, write, and format Mac-formatted disks and DMG files. A single-user license key costs $59.00 .