Treadmills are great. Sole is a good brand for the money. There are (sadly) a bunch of gyms closing so a few deals are to be had on Craig’s. That said, unless it’s so snowy that you can’t get traction, there is no reason to stay inside for running. An easy and inexpensive approach is to get a set of thin wool thermals and socks (I really like Duckworth) and layer them under normal run pants and a cycling jacket. I wear mine over 1/2 tights because that ‘part’ of the body is actually at risk to get cold in theses temps. Wool liner gloves + cheap shell mittens. Pro tip is that you should bring a second headband or hat - if you sweat number 1 thru, the cycling jacket means the dry cap can be swapped out in a few seconds because the pockets can be easily accessed without stopping. Same thing with the shell mittens - start the run with em on, but once the engine gets hot, it is as simple as pulling them off and tucking them into the cycling jacket pockets. It only took 20 years for me to figure this system out...