Cheapo 12v Impact wrench $40, takes the wheel nuts off so much faster than by hand. Very hand for swapping from road tyres to offroad tyres, back when I bothered.
2.5 t hydraulic floor jack a bit like this one cost me about $100 from super crap auto. Love it.
Stick welder, $100, worth every penny.
Leatherman or similar... Get a good one, not a $20 copy. Save many broken knuckles, stripped bolts and burred screws.