I paid £20 for mine and it was second hand called My Guide. It was a brand for Asda only. Does everything it should as long as you realise it, just like any other sat nav doesn’t take you the best way.
Example, if you went from Pontefract to Stoke it would take you the shortest route as the crow flies through the middle of Sheffield and the Peak District.
You know you’d down the A38/A50 or M62/M6 so use it within the limitations and use your common sense and I reckon it’d be fine.