Your node uses as much incoming bandwidth with or without pruning; pruning just means your discarding old blocks. Pruning doesn't let you avoid downloading them in the first place.

Pruning will indirectly reduce outgoing bandwidth if your node accepts incoming connections, because nodes downloading the whole blockchain can't download it from you. But you can limit bandwidth usage in other ways too, so you can still run without pruning if you want regardless of how bad your internet connection is.

Personally, I only use pruning on nodes without much hard drive space.