The Monarch brand was made by Federal, usually seen in chain stores like Western Auto, KMart, and others. Many of the bigger companies produced ammo (and firearms) specifically for store brands (Sears "Ted Williams" line, Wards "Hawthorne" line, Western Auto "Revelation" line, and others). Usually a little lower price than the "big brand" products, but sold by the trainload to the bigger chain stores, and probably just the same as regular production.
Probably an interesting niche for collectors.
The 148-grain wadcutters were very popular for target and practice ammo, also about the lowest priced .38 Special ammo on the market. Back in the 1970's we used remanufactured ammo with wadcutters on the police department range; the brand name was 3-D and if I remember correctly the company provided ammo in our returned cases for under $2 per box (in multi-case lots, of course), less than $40 per thousand round case. We were required to qualify twice each year, but we could go to the range and shoot just about any time we wanted to. At that time new factory .38 Special ammo was about $5 per box at retail stores, maybe $9 or $10 for the fancy new hollow points.
Nearly a half-century later I am still using the 3-D cardboard boxes I collected from the police range for my reloaded ammo. I must have a hundred or more.
I got into reloading at that time. Primers were about $7.50 per thousand and bulk powders were under $5 per pound. I dug tens of thousands of .38 wadcutters up in the pits of our indoor range and used those to cast my own bullets, so the only cost was bullet lube. I figured my reloads at about $1.25 per box.