Hi Brendan,
I fly small...Cox .049, AP Wasp .061, up to a twin .074 Mosquito.
So I say the following just to show you can start small and scale up as desired on your terms with a little creativity:
I'm cheap...and I wanted to start low dollar. I made my battery box from 1/8" plywood. It literally is two clamshell, or 5-sided boxes/halves that each have brass tacks with foam underneath (for springs) for battery contacts. The contacts get squished to the batteries (4 side by side in parallel) when I place the batteries in and ziptie shut. All contacts come out to a lamp cord that was soldered to each tack and terminates in alligator clips. Battery replacement is simply cut ziptie, open, replace batteries, ziptie again. This thing is UGLY!
This worked fine until I wanted a pit box for an electric starter, tools, extra props, extra glow heads/plugs, fuel, 12 volt battery...and a power panel. I don't regret scaling up. My pit box makes short work of starting my twin .074 Norvel-powered DH Mosquito.
For the $ part you showed...
You may want to check eBay. I just looked and found starter kits that had two T-wrenches, bottle, and rechargeable glow "starter."
There are also glow "starters" that have built-in pulse regulators inline on the wire. These get connected to a small 12 volt battery like in security/emergency lights. I don't know how well they hold up, but can see how this would be a good way to get the benefit of a power panel (adjustable glow plug output) without actually having a power panel.
Enjoy your entry...I hope your boy does too! Mine bailed on me.
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F142270476910https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F292597307550