Geocodio is designed for you to be able to see if it's a fit for what you need and your budget without having to talk to someone first.
For standard Geocodio, the first 2,500 lookups per day are free. This includes both the spreadsheet upload tool and the API.
You do not need to add a credit card to your account to be able to use the free tier. You can just sign up and start processing data right away.
You can use this tool to test a single address/latitude-longitude pair and see what is returned by the different categories of data appends. There is no signup required, and the data is not stored.
A "lookup" is one geocoding query (forwards or reverse). Data appends are considered an additional lookup. For example, 100 addresses plus timezone would be 200 lookups. You can use the Pricing Calculator below to estimate the cost for the data you need.