3D printers for dummies - can anyone speak to what's required for making Packout inserts?

Hi all, my GF asked me what I wanted for the holidays, and before I could even get a word out, she said 'I bet you'd love a 3d printer to make inserts for your Packouts!'

I was too surprised that she even knew Packouts by name, or that 3d printed inserts/attachments were an option.

Considering I'm not exactly a tech geek, can anyone speak to how easy (or not easy!) it is to make Packout attachments using a 3d printer?

For example, let's say I get one...

1. How long does it take to make, let's say, an attachment that would help me organize my Dewalt batteries?

2. How hard is it to get the info (the code?) for things like this? Are they sold? Free?

3. How long does a typical print job take?

I keep hearing 'it's so easy!' and 'there are SO many options you'll be printing things you never dreamed of'....BUT...I'm not exactly holding a PhD in IT or anything.

Just wondering how useful, fun, and realistic these 3d printers are...and how many here have it as a side hobby/use it for Packouts?