I'm working to build a small product that I'll sell at local art fairs, market place, etc. It's possible I may sell on Etsy someday but not likely for awhile. I'm using a small ATtiny85 to control ~10-15 addressable RGB LEDs. There will be a few programmed lighting patterns that will be accessed through a simple button to toggle on, through the patterns, and turn off.

Battery operated won't work since the LEDs will be on for 8-10 hours per day. It doesn't require much power but I was thinking a simple 5v 2a wall power supply. What's the safest way to correctly provide this power to the product? Should I directly solder the power supply or connect it through a soldered on barrel plug? Do I need to use heat shrink tubing?

I've never prepared to sell a product before as everything I've done has been for my own use. Any best practices or resources you know about?