Can anyone suggest a budget 4g smartphone for wifi hotspot tethering

Hi,

I have been using my Lumia (MS) Smatrtphone as a wifi hotpost with Smarty Unlimited data ...as where I live there's no chance of a phone line and router...

I am concerned that if the phone fails, I will be stuck with no internet on my laptop or Netflix/Amazon/Now TV on my tv...

can anyone suggest a budget cheap and cheerful 4g phone that I could use as a backup?

doesn't even matter if it's second-hand, so long as it has a decent wifi hotspot and 4g

thanks