df <- rnorm(1260, 0.06, 0.2)

Error: Aesthetics must be either length 1 or the same as the data (1260): x

price <- rnorm(1260, 0.06, 0.2)

date <- c("Jan", "Feb", "Mär", "Apr", "Mai", "Jun",
          "Jul", "Aug", "Sep", "Okt", "Nov", "Dez")
date <- rep(date, 5)

data.frame(date=date, price=price) %>%
  ggplot(aes(x = date, y = price)) +
  geom_line() +
  labs(title = "Stock Price Chart", y = "Price", x = "date")