You need to research more of what you want. there are hundreds of kits and at at least that number of engines. I am building a modified Long EZ for instance. Some guys put cheap O-200 engines in them, some O-320s, some O-360s, mine will be an IO-390X. Prices range from a few thousand to well over $30,000 for the engine. Instruments range from a few thousand to over $100,000 depending on how you want it set up.

Go to Aircraft Spruce and specialties and look at some of their kits. Its hard to price it till you know what you want. There are guys that can build one specific kit for half of what someone else can because they use different engine and instruments.

Google aircraft spruce and see whats there, they have a good list of kits.

Then you have plans built like mine, no kit but good plans. You make the parts. Sometimes cheaper, but takes longer.

Lots of options out there.