Are microscopes easy to use or complicated?

I learnt how to use one when I was six, and it cost a fiver at the time.  That would be about £60 today, which is something like USD100 or so.  You can still get microscopes of that kind and their design hasn't changed for something like a century.  There are polarising and phase contrast microscopes and things like oil immersion lenses, but a basic microscope isn't hard to get the hang of.  I have personally observed Colpoda from the soil in my back garden, also Vorticella and Amoeba from nearby streams, and the latter I did when I was, as I say, six.

The type you would have at home are fairly simple.  You might want to look into one of those things that connects to your phone, so you can also takes pics of what you are viewing. Google "phone microscope" and several will pop up.  they are a lot cheaper than a microscope.