example.R

my_data %>%
  mutate(
    category = case_when(
        amount < 10000 ~  'under_10k',
        amount < 50000 ~ '10k_50k',
        amount < 100000 ~ '50k_100k',
        amount < 500000 ~ '100k_500k',
        amount < 1000000 ~ '500k_1m',
        amount > 1000000 ~ '1m_plus'
    )
  ) %>%
 group_by(category) %>%
  summarise(count = n())