Cheapest mobile broadband backup option

So, I'm with Vodafone broadband on a fibre connection, when it works it is great but I do get occasional problems, in the last year it was down on 4 separate occasions one of which lasted 2 days.

I have a decent Draytek modem that can use a USB dongle as a backup to the main broadband so I am seriously thinking of using this option.

Quite simply I am looking for the cheapest one year pay-as-you-go option for mobile broadband, my usage would potentially be very small so caps are not a problem, so far the cheapest option I can find is here:
https://store.meteor.ie/mobile-broadband-plans/pay-as-you-go/

For €30 every 180 days I will get 50gb which should be way more than I need and a total cost of around €60 per year.

Just wondering if anybody is aware of an even cheaper option?

TIA