IMHO Better buy the CDs of the
cassettes u need.
There i one more way :
Requirements - Headphone,cassette player,cassettes and pc
1. Start the cassette player
2. Put the cassette in it
3. Switch on ur headphone.
4. Make ur cassete player on HIGH volume
5. Start Recording and save it in mp3
I know its a lame method . You can use softwares like Windows Sound Recorder or Audacity etc to record