Winter complete wheels 245/60 R15 – where can I get them?

Servus together! I’m looking for my Ford Ranger (EZ 89) winter complete wheels. I have the following questions and would be very happy about help! 1. Is my guess that winter tyres are cheaper in summer? 2. Are steel wheels recommended for winter? What are the disadvantages (have they got one?)? 3. Where do I get tyres in size 245/60 R15? I found only one or two (Chinese) tyres on the internet. Alternatively, I would have found the size 215/75 R15, which gle me I’ll take you to question number 4: The comments in the vehicle license are below: “formerly also 215/75 R15”. Does that mean that I can still put them on? Thank you very much! Best greeting, Tom