What to get for a microscope?

[Harry]

Hi,

My youngest son is asking for a microscope to play with and we went to Zanny
Branny (a toy type store) to look for one.  They are exactly like toy.
I have three kids--oldest one is going to High school taking Biology next
semester. Second one maybe will soon find it (microsope) useful.
What should I get at what quality and approximate $ in US?

Though I am a science major guy, I am always frustrated with my very limited
knowledge toward biology.  My six years old son finally lighted up the hope
of heading to bioscience field.  I am excited and I don't want to buy him a
junk.

I found the traditional one is about the same design as 30 years ago.  There
is one with an USB port to see the image on computer screen.  Should I
consider to get him an traditional optical microscope or the new USB design?

Thank you for any input.