We pulled up the carpet in the basement and put in vinyl plank. We were going to be pulling up the carpet on the main floor too. We couldn't just have a lonely little island of carpeted stairs in between! But what would we do? We talked about continuing whatever flooring choice we made for the main floor down the stairs, but eventually decided against it, thinking it would be too expensive and difficult to do. After showing Bob Thrifty Decor Chick's stairs (the first one I saw, and boy was my mouth hanging open when I saw that one!) and some others I'd seen online, I finally convinced him it'd be worth a try to stain the steps. If it didn't work, we could plan B it with a can o' porch paint!
First I had to pull up the carpet. That was not so hard. Taking all the pad and especially all the staples out, that was the hard part. I ended up using this plain old staple remover quite a bit.
I also had some pliers and the end of the hammer.Our stairs weren't in the best of shape, but we just made it work!
We did a lot of sanding. Sanding by hand, sanding with our power sander. I also filled some of the holes with stainable wood putty. I don't know that I'd bother with it too much if I did it again. It was good to fill deep, small holes, but not good for evening out big patches. It did stain a little differently than the rest of the wood, but each piece of wood stained a bit differently anyway, so it's not too noticeable. The risers were like dry, flakey woodsville. I used some filler on them too, those were getting painted anyway, so it didn't matter as much. We decided to use a pre stain wood conditioner. I don't know how much it helped, I like to think that it did. That stuff was stinky though and it had some scary warnings on the label. That and the top coat were the only things we paid full price for though. I hit the jackpot in the oops paint section.
I got the stain for $2.50 since the can was dented (it was marked down and in the oops section). I got a small can of black (or close enough to black) exterior paint for $1 (marked down from like $13). The white paint, for the trim along the sides, I already had on hand.
So after getting all the staples out, sanding the heck out of it, wiping it all up very carefully, I pretreated every other step then stained. 
I didn't bother taping at this point, since I knew I'd be painting all the other surfaces over. After waiting, polying, and waiting some more, I covered those steps with paper and did the same thing on the others (several days ended up passing before this part). After all the stairs were stained and coated and good and dry, I taped around the risers. 
I mixed some of the black paint in with some primer I had on hand and primed the risers. I used one sheet of paper to cover the step I was working over and moved it as I went along (it would have taken for ever to cut paper for each step and tape it carefully avoiding the risers) The next day I painted them over with the black paint. After all that dried, I removed the tape and taped along the trim on the sides. After doing two coats, I took the tape off. Some of the paint got through the tape. I tried to clean it up as best I could. It came off quite well from the treads. I still need to caulk a few spots on the trim and touch up the wall paint, but here it is- before and after.
