I just dug around and found a pack of those I bought as a spare set probably 40 years ago, its got a $2.49 price tag on it from a local bike shop.
They sort of went out of favor when tubular tires faded away. It became more popular to buy kevlar lined tires or to add a protective strip to the inside of the tire to protect the tube.
This all added weight though and wasn't common among more serious riders.
Back in the day, I rode with guys who used all sorts of tricks, including one guy who if not just extremely frugal, was inventive.
He would save old cans from Tomato paste, cut the rim out of the can carefully sanded it just right, then he soldered that to a couple of pieces of an old spoke, and took the rest of the spoke and formed the bracket to attach to the caliper bolt. He connected the bracket to the 'scraper' portion with two tiny bits of clear tubing or wire insulation stripped from some cable. He must have made 20 sets of them before perfecting his personal design that would ride just barely touching the tire but not making any noise or resistance.
He said that most of the factory designs used plain round wire and that wouldn't 'catch' small bits of stone or glass as well as a cupped scraper.
The rubber or connector was required to prevent damage in the event the scraper got bent or the bike was pushed backwards and the thing caught the tire wrong. Two spare sets were always in his tool kit, along with a patch kit, tire tools, and assorted tools. His tool kit was kept in a second water bottle holder in a custom made aluminum screw top can made to fit in place of a water bottle.
Many guys back in the day only ran tire savers on the rear tire since it carried more weight, but myself, I always seem to get front tire flats.
My rear tire rarely picked up anything. (Maybe because it was already stuck in the front tire?)
Personally, tire scrapers only really were effective on a very smooth tire, if there was any tread or pattern they either made noise or bounced, or missed the debris altogether.
Buy a set of good tires, maybe a set of liners or thorn resistant tubes. On a heavy bike with a heavy rider, the difference won't be that noticeable.
For what they want for the tire savers these days, I think your money would be better spent towards better tires with some puncture resistance.
Rubber these days has also come a long way, good tires seem to hold up a lot better than those we had 40 and 50 years ago.