1st generation ipad mini - SIM card?

That would depend - is it a WiFi only iPad mini or a WiFi+cellular iPad mini? If it is a cellular model, the nano SIM slot will be on the left side.

iPad mini - Technical Specifications

Identify your iPad model - Apple Support

Hi

Have a look at a mifi wireless router you can run up to 10 devices at once works anywhere you have a mobile phone signal.

Pay & Go or contract look on EBAY /Amazon at a Netgear aircard.

Cheers

Brian 🇬-1F1E7;