Here's the things I would put in a dyi hot sauce making kit are:
A food processor is the secret to making good hot sauce so that everything is evenly mixed. Combine it with a pH reader to be sure that the sauces are shelf stable. Xanthan Gum is a thickener that is hard to find in stores.
With these 3 things, you can get the rest of the ingredients for most sauces at a grocery store. From there its just finding a recipe to make and storing it (I use pint mason jars).
Here is a pineapple habanero recipe that is pretty basic, you can alter it to suit your tastes and heat tolerance. I sometimes add garlic and spices, add apple cider vinegar, remove the cilantro, add raspberries and add scorpion peppers for heat to give some ideas on what can be changed. Most sauces need Xanthan gum afterward to thicken them up.
The easiest recipe I've made was this Mango Habenero sauce that tries to emulate Buffalo Wild wings. Its pretty much all sugar but that hides the heat really well and thickens the sauce up a lot when cooled.