Like, you had no choice, so if you had a family that was just making it by, what happened to them when you were not making enough money to pay their rent?
Rents were lower back then even in inflation adjusted terms (in other words rent has gone up since then faster then the general rate of inflation).
This link only goes back to 1960, but that's most of the time since WWII
https://www.apartmentlist.com/rentonomics/rent-growth-since-1960/
This goes back to the 40s but only looks at New York
https://ny.curbed.com/2013/11/21/10172014/what-would-50-in-1940-rent-a-new-yorker-today
Rents were lower in the 40s even in real terms, for several reasons. One is that demand was suppressed by the depression, and then by sending people off to war (single soldiers wouldn't keep and apartment back home). As the economy heated up you had price controls and rationing keeping prices down. The price controls included rent control - see https://siepr.stanford.edu/sites/default/files/publications/fetter.rentcontrol.ww2__6.pdf
Also on the average houses and apartments were smaller back then. https://www.propertyshark.com/Real-Estate-Reports/2016/09/08/the-growth-of-urban-american-homes-in-the-last-100-years/
Then you also have base housing, and things like the wife (or whole family if there are kids) living with her parents or potentially his (her in-laws).
There was a system of family allowances that allowed a serviceman to have part of his pay deducted in return for both the deduction and an associated extra contribution provided by the government to be sent to the man's family.
As an example, a man who applied for an allowance to be sent to a family consisting of a wife and one child would have $22 deducted from his monthly pay but the $22 plus a government contribution of $58 would be sent to his wife. Thus if he were getting the minimum $50 private's pay he would be left with $28 while the wife would get $80, quite a bit more than the $50 a month figure would suggest. The amounts of the deduction and the government contribution varied depending what dependents the man had, see here. Generally speaking, the government contributions for wives and children were fairly generous, the contributions for other dependents such as parents and siblings were rather less so.
In addition, there was a deduction called "allotment" that simply allowed the serviceman to have part or all of his pay sent somewhere else rather than paid to him at his duty station; this could go to family, a bank account, or whatever, there was no government matching contribution for allotments.