Yes. We built a second story in 2013. Our home was built in 1963. The only thing we had to do in the basement was add an additional primary support wall right next to the existing one (we have a long support wall that runs down the center of the home), and that was just for extra peace of mind, didn't really require it. No steel beams or anything like that were needed. We gutted 2 first floor bedrooms and made that our master bedroom, then on the second story we made 3 bedrooms and a full bath, and so that is the kids' floor. The addition was 750sqft on top of the existing 1460sqft ranch, and one of our good friends was the contractor. He did the stairs, exterior structure, siding, windows and roof. We then completed the full interior on our own. The part he did for us cost us $42k and we paid an architect $250 for the drawings. We did the rest ourselves including the walls, HVAC, plumbing, electric and flooring but we did it over a period of about 7 months, and I guess if I had to do a really broad guesstimate we probably did all that for about $20k.
Of course materials are way up now, and we didn't do really expensive finish work up there (less expensive wall to wall carpeting, very basic bath vanities that I knew my 3 small kids would beat up anyway, etc). And costs are going to depend on where you live, who you hire, and all that stuff. This home is in semi-rural Western New York.
I don't regret it at all, all 3 of my kids have their own room and all of their things (except toys which go in basement play room) are on their own floor. The only thing I don't like about the addition is where we had to place the stairs -- stairwell is at the end of the hallway going towards the garage, there was no way to really do an open staircase or something near the primary living area of the house because we would have lost our home office on the first floor.