Q: Labeling Syntax in R Boxplot Trying to establish "range" labels on a boxplot:
x <- getURL('https://raw.githubusercontent.com/dothemathonthatone/maps/master/maindf_2_Anon.csv')

maindf <- read.csv(text = x, row.names=NULL, head =TRUE, dec = ',')

maindf$fee_per_inc <- as.numeric(as.character(maindf$fee_per_inc))

summary(maindf$year_hh_inc)  



Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
   7501   35000   50001   56446   75001  500014 

maindf <- maindf %>% 
 mutate(category = cut(year_hh_inc, 
                       breaks = (quantile(year_hh_inc, c(0, 1/4, 2/4, 3/4, 1), na.rm = TRUE)), 
                       labels = c("€ 7,501 - € 35,000", "35,001 - 50,001", "50,002 - 75,001", "75,002 - 500,001"), 
                       include.lowest = TRUE), 
        vals = 1) 

maindf <- maindf[maindf$fee_per_inc > 0 & maindf$fee_per_inc < 0.0001, ]

box  <- boxplot(maindf$fee_per_inc ~ maindf$category, col = 3:5)


I would like to label each box with the ranges from the summary call. For some reason it is only picking up two boxes. Does someone have an idea on that?
And I sure wish there was something that could be done about those colors? 

A: The labels are already "there", but R's native plot method will drop axis labels if they are going to clash, so you just need to shrink the axis text:
boxplot(maindf$fee_per_inc ~ maindf$category, col = 3:5, cex.axis = 0.9)



A: The reason why the labels are not shown in full is simple: they are too long. The solution is simple too: just adjust three arguments to boxplot: 
First, increase/decrease the margins around the boxplot so you have more space for spacious labels by adjusting the values in mar; for example, you make the space under the boxplot large enough for the lables to fit under: 
 par(mfrow = c(1,1), mar = c(8,4,1,4))

Then/Or adjust the character size of the axis labels by decreasing cex.axis(it defaults to 1)
And finally you can set las = 2to flip the labels' direction.
You also mention colors as problematic: you can easily change them in any way you want by defining the colors of your choice in the argument col:
boxplot(women$height, women$weight, 
        names = c("A long variable name", "B another long name"),
        cex.axis = 0.8,
        las = 2,
        col = c("red", "blue"))


