Logz.io charges based on daily log volume and retention length.
For example, shipping 1 GB per day and holding the data for 14 days costs $89 per month (on the annual plan). If you need a longer retention of 30, 60 or 90 days, that will increase the price. If you need to ship 100 GB, that will increase the price as well. The price per daily GB reduces as the volume grows.