A live CheckUpDown account only costs US$75 per year. We also offer 'check group' accounts (a group of 5 accounts or more) for our users who want to monitor multiple sites/URLs. If you want more than 5 accounts in your check group, additional accounts are charged at the same rate of US$75 per annum.
We can offer reasonable volume discounts if you want a large number of monitoring accounts.
Please contact us if you would like to consider opening live monitoring accounts. You can of course still have a free 90-day trial of CheckUpDown, although you are limited to only one free trial - you can not repeat the 90-day trial over and over again on the same or different accounts.