Not Ranked
The cheapest way, assuming that the prior builder did not screw something up significantly, is to buy an already started kit that someone couldn't finish. The seller will eat some percentage of the price to get rid of the car.
You can always go cheap on the engine now (one of the biggest costs outside of the kit) and replace it down the road with a better engine. 300 HP in one of these cars will get your attention in a hurry. While we like bragging about all of the HP some of our cars have, outside of a race situation most people on this site never use all of the HP their cars produce.
It's your car and your money, do what you want wth it. Just remember to factor in some additional time and expense due to parts shortages due to COVID related shutdowns in factories and shipping. It may take a little while for the industry to fully recover, so you might have to wait weeks and pay a little more for a part that takes 1 hour to install.
Jim
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