I don't get car poeple at times ?

Please don't take this the wrong way but?

I don't get why some cars have lots of money in them but not yet finished and told it's not worth the money it has to be sold cheap.
But yet some guy buys a 1000 to 1500$ rust bucket and in the long run spends more time and money just on the rust alone, then it would have took to buy the car almost finished at the price that's been invested in.

well in my case i would like to buy one that has had alot of money invested but not yet finished but unfortunaly they probably between 3000 and 5000 but i cant drop that amout of cash on one because i dont have it

but i can drop 1000-1500 on a rust bucket and put money into it a little at a time thats why i think its hard to decide to buy parts here and there if you have a car to start with

plus i love a challenge and the coments i get from ppl on my hard work theres nothing more satisfiying