garmin models

hi, to all on the garmin site. I have a few tomtoms that i know my way around which i lend to family and friends for testing as i don't drive that far these days, it's just a bit of a hobby in the cold winter nights. I'm at a bit of a loose end for a project and thought about something different to tomtoms. i don't know that much about garmins, but could someone suggest a garmin model to purchase second hand that i could play about with to learn about them.
kind regards.

It's not so easy to suggest a device, because there are various generations with a lot of models with different features.
If you want to learn something about the system of current models, you need a device from 2010 or newer, e.g. nuvi 13xx, 14xx or nuvi 23xx, 24xx, 25xx.

i splashed out on a used zumo for my bike and it has two maps on the internal memory and one on an sd card. i've also downloaded from this site a new map and installed to a new sd card, renaming it gmapsupp, it works very well. What i would like to know, is it possible on the p.c. to read these img. files to see which map is which? i,ve looked at many tuts but can't seem to find an answer.
I also would like to know how to place two separate maps onto the same sd card, i.e. how do i rename them differently so one wont overwrite the other.
kind regards

use GMAPTOOL (freeware) to find out, which image file contains which map,
on older devices you only can use one image file gmapsupp.img in folder Garmin on SD
only newer device series (from 2010 and later) can use more map images with any map name in folder Map (internal as well as on SD)

more about supported map names on different devices >>>here