It looks VERY professional but you'll have to spend a few hundred dollars at a pop to get these produced. They will print as few as 50. Their turnaround time is about 15 working days. 5,000 would be about 85 cents each. Now, a few words about producing audio cassettes.
Audio cassettes are fairly easy to produce and inexpensive to duplicate.
You can actually do the recording yourself with an inexpensive tape recorder from your local electronics store. You can buy the equipment and do it yourself or you can have it done for you. For tape sets, you can purchase albums for 1 to 3 dollars each, depending on size. Both of these companies can also provide albums for tape sets or you can usually get them less expensively from Blackbourn Media Packaging. Or, you can produce a moderate quality video with an inexpensive video camera.