You can connect them to a *compatible* digital readout. The probe in the link is a 100 ohm RTD. That's different than a 10K ohm NTC or a type K thermistor. As long as the readout is expecting the probe you have, it will read out.
In many cases it's cheaper to buy a readout + sensor than to buy them separately. The gotcha there is that you then need to adapt their cheap sensor to your setup.
Cheap sensor + probe, brand new - eBay $6 delivered. Plus stuff to make it like the one in the picture total -> $35.
Sensor like the one in the picture - $25. Plus cheap eBay PID total -> $35 to $40.