Date unknown, but some Sears swing sets sold for around $40 in 1969, so this could be a little before that, given $30 was a common price point in the '50s-60s. These were very common in backyards throughout North America by the '50s. Some models had appointments like ponies to ride, tires, or even jungle-gym type attachments.
The '50s sets got safety improvements in the '70s, and by the '80-90s changes to safety laws saw the metal tube sets phasing out in favor of updated designs. It was possible for children swinging in unison to tip the structure over if not cemented down, not to mention opportunities for cuts and pinches. About 1 in 25 owners in 1971 reported an injury requiring medical attention.
Here's a photo of a metal tube swing similar to the Sears ad model, without the slide option.
Swings have been around a while. Here's a small model of one circa 1400BC from Crete, specific year unknown.
Seriously, I remember even at a young age being able to rock the entire set back and forth. I guess the safety mechanism is that eventually your ass doesn't fit in the swing anymore.
Oh, and I remember the slide feeling unstable as hell.
I had a swing set + slide as well. Pretty rock solid because my mother knew that it should be secured. Each part that touched the ground was kept in place with a big cylinder of cement just below the ground. There were definitely swing sets out in the world that were scary in retrospect, but I didn't worrty about that as a kid.