Hoping for a bit of advice from anyone up on their in-car tech

Laura is travelling a lot more for her new job, and is regularly doing site visits and driving to offices based in the neighbouring county. So far she has been relying on her mobile but isn't finding it ideal (reception drops off, it uses data, battery isn't great etc. etc.), and now we're looking for a dedicated sat nav for her to use instead.
I've been to Halfords and tbh most of it went over my head - I've never owned one so not sure what is needed to get by.
We're budgeting about £100 but anything under would be awesome. Hoping somebody can recommend something decent

Cheers,
Josh