Both of those bills are plausible because these apps stack two different kinds of charge.
The subscription is the flat part. Entry tiers for the common driving apps tend to run somewhere in the range of $50 to $100 a month for one or two users, with team plans and higher record limits going up from there. Confirm current pricing on the vendor's own page, because tiers and limits change often.
The usage part is per record. Skip tracing, which means matching an owner name to phone numbers and emails, is typically priced per hit, often somewhere between 10 and 30 cents. Direct mail sent through the app usually lands around 40 to 80 cents a postcard including postage. So a month where you log 300 addresses, trace 200 of them, and mail all 200 twice looks nothing like a month where you just drove and logged.
The notebook version does work. County assessor records are free in most counties, you can type addresses into a spreadsheet, and you can buy stamps. What you give up is speed. Manually looking up 100 owners is an evening of clicking, and the app does it while you're still parked.
One thing that catches people who come at this from the service side: the mail and calling that follow a sighting are subject to marketing rules, and phone outreach in particular runs into do-not-call and consent requirements that vary by state. If you end up offering outreach as a service to investors, that's a question for a lawyer before you take the first client.
