Well, I added something new to the spreadsheet. You'll see a yellow row above the turnip prices. This will show you the current day's highest price, along with who has that price and which row you can find them in.
It took me an hour or two to figure it out, but I finally did it. I had to make hidden rows and columns that calculate the date, what day of the week it is, and the highest price for each individual person for each day! You won't see any of that, though.
Anyway, the final formula, excluding all the hidden stuff, looks something like this:
=CONCATENATE("Today's highest price is ", if(text(B11,0)="Sunday", "", if(text(B11,0)="Monday",max(I12:J300), if(text(B11,0)="Tuesday",max(K12:L211), if(text(B11,0)="Wednesday",max(M12:N211), if(text(B11,0)="Thursday",max(O12
211), if(text(B11,0)="Friday",max(Q12:R211), if(text(B11,0)="Saturday",max(S12:T211)) )))))) , " Bells, belonging to ", index(G12:G211,MATCH(K9,V12:V211,0)), " in row ", match(K9,V12:V211,0)+11)