The on the spot fine is usually between € 50 - € 200, while the standard administrative fine is € 150. In more serious administrative proceedings, this can technically climb as high as € 500.
If you pay the fine within 15 days of receiving the notice, it is usually reduced to €100.
If you drive onto a toll road without a vignette, you will not be fined as long as you purchase a valid e-vignette before midnight on the same day. The system checks the daily logs against the database at the end of the day. If a record of payment exists for your plate on that date, the violation is cleared.
Please note: Even if your car carries foreign license plates the fine will be sent to your home country and enforced within the EU.
You can order your Slovak e-vignette comfortably here.
Related articles:
How is the Slovak e-vignette checked?
Can I drive into Slovakia without a valid e-vignette if I avoid motorways?
Which roads require a Slovak e-vignette?
Do I need a Slovak e-vignette if I only drive in Slovakia once?
Driving with an expired Slovak e-vignette