I don't have a lot of money and I want something for deer season plus plinking plus whatever. I was thinking that a nice 91/30 might be a good start.
Anyone ever regret buying one?
I'm going to step out on a bit of a limb here and say "YES"
You already list all of the reasons why you shouldn't own one. They aren't a "good start" unless you are a bit of a history buff and live in a location where hunting as well as milsurp ammo is easy to locate.
As Smellie so aptly pointed out, it all depends on condition. Condition is everything when it comes to accuracy.
It also depends on your eyesight, physical strength and ergonomics.
The MNs were designed to be battle rifles that could be used as spears or clubs and weigh in accordingly.
They are cheap to acquire but so are sportered Lee Enfields. Most gunshops will have a couple of those stashed away somewhere for as low as $100, for a decent one. Then again, it's buyer beware as well. All used firearms are. Take someone with you that knows what they are doing, when you actually decide to part with some hard come by cash.
Recently at a gunshow, I picked up a very pretty Mod 94 30-30 Winchester for $200. It retained about 60% blue and was one of the models made in Japan, with a Birch stock. It had a bore that looked as new. I only had the rifle in my rack for an hour before a youngster came along with his Dad and proposed an interest in it as his first rifle. We made a deal where I came out even and a happy youngster and his Dad, walked away to look for some ammo that wasn't to be found at the show. Not only that but flipped a rifle that had been registered at one time, twice in the same hour, to disappear into limbo.
Nope, I honestly think that from your first post and second post stating that you want to shoot coyotes as well that the MN 91/30 would be a poor choice.
At that same show, I also sold a 70s built Rem 700 in 270, complete with a period Bushnell Scopechief, sling, box of ammo for $400, all in.
You need to get out there and look around. The EE here is a good place to start but most of the sellers have a high opinion of the value of their offerings. Don't be afraid to barter or dicker on price. If prices are firm, unless it's something really special, move on because there is a lot of stuff out there for sale.
Take out an ad in your local paper, you will get more offers than you can handle.
I have had several firearms given to me because people just want them gone from the house for whatever reason and don't want to deal with other people.
The Mosin is a fine rifle for its intended purposes and in many areas of the world it was and still is used for a hunting rifle. In many cases, highly modified for ergonomic as well as esthetic reasons. That is a whole different issue and not really worthwhile anymore unless you want the work.
One man's junk is another man's treasure. The MN can be either. It all really depends on the man and his personal preferences or needs.