What is your opinion on these two nikon 35mm film cameras?

Nikon N60
Nikon Em
and what do you think is a reasonable price to buy these two cameras?

I'm a beginner at photography

I'd avoid the EM as it was an economy 35mm crippled in many ways. In my hands, it was way too small, as Nikon was trying to capture some of the Olympus OM and Pentax ME/MX market for compact 35mm SLR's. The EM was totally automatic, and had no manual settings. That told you who it was designed for.

The N60 (I have two of them) was a nice mid-sized 35mm that had manual and automatic options. It also, unlike the EM, took autofocus lenses. In fact, the same Nikon and 3rd party autofocus lenses that I used with my N60, are still usable with my D50, D70, D200, & D300 cameras today.

As for price, I've seen the EM going for under $50 and the N60 going for under $80, both with lens.

Neither gets my hard beating any faster. The N60 was a fairly basic, budget Autofocus camera from the mid 90s. The EMwas a late 70s answer to the OM-10 and the AE-1 by making an FM-lite camera. It's manual focus and aperture priority.

I would not pay more than 30 euros body only for either of these and I'd expect one in very nice condition for that kind of money

Spend a few more bucks and get e.g. A N80 instead. It's a much better camera (except that it needs special camera batteries instead of AA ones). You should be able to get one used for no more than $50 in good condition, or $80 with lens.