In short order, an old cheap plow truck will need repairs. If You can’t do a lot of the labor yourself they become prohibitively expensive. It doesn’t work. If it did, there would be none for sale. The best thing for single purpose snow removal are snow blowers. One mounted on a small tractor is good especially considering what it can be used for otherwise. A used plow truck will continue rusting when not in use. Pass on the idea.
Plow trucks work as money makers only if they are inexpensive enough to keep in good repair. That means" fairly new" or very cheap to repair while you generate income with them. That’s not you. C
My neighbor is a contractor who has several trucks. I worked for him. You must be very hard on a truck to do the job. That means new trucks with warranties, if you can find a dealer who will do it, or have your own mechanic… My neighbor does both.