What are the cheapest options for simple, but user-friendly data entry?

Right now all I have is an smartphone, which is cheap (because I don’t have to buy another device), but not user-friendly (because it’s so small).

Perhaps there are good apps for Android for user-friendly data entry (i.e. a simple spreadsheet app that you can easily enter data into cells and maneuver through many rows of data) that I don’t know about.

Or perhaps there are mobile devices that are already made for such simple tasks. I’m talkin’ like two columns and a few hundred rows of data max per project.

This is the only use I would have for this device, so it need be nothing fancy.