You can export the CMS physician fee schedule, if that will meet your needs. You'll get the code and short description for anything listed on the fee schedule.
The limitations of this are:
1) It's only for the codes that are on the physician fee schedule.
2) It's a short description, not the full description from the CPT book.
However, it's free. It's worth considering if it will meet your needs, even with the above limitations.
Otherwise, if you truly need the complete CPT set, purchasing from the AMA is the only legal option to my knowledge. CPT is copyrighted by the AMA.