A well stocked toolbox. Not just a random assortment of things but a well considered, well stocked toolbox with everything you need to tackle basic home repair.
To all those saying that tools are too expensive, they are not. Everything you need to tackle most home repair scenarios can be had under $100. Will you be turning screws by hand and adjusting wrenches? Yes. Will it be enjoyable work? Probably not, but you absolutely can have a good set of very basic tools for under $100 then add to it over time.
Get a hammer, adjustable wrench, angled pliers, razor utility knife, and 11-in-1 screwdriver. Buy additional tools as needed.
Seconding this though, I've been building out my toolbox for the last couple years, and it's nice knowing if something goes wrong, I probably have the tool I need to do the job.
If I don't have the tool, I soon do have the tool. My toolboxes are not well thought out but built from years of "this would be so much easier if I had X.... Screw it, I'm going to the hardware store"