How do you like to play?

[MR L A]

1 hour ago, putnamto said:

Isn't their a way to make it so you buy individual parts from the tech tree instead of the whole node? 

Yeah, you just buy them as you want to use them in vab/sph instead of buying the node

Or do you mean buy with science and not funds?

[Zeiss Ikon]

There isn't a way to change parts buying mode in an existing save (at least not without save file editing, which I've never tried).  In a "new game" there's a setting in the difficulty settings to "require individual parts purchases" (actually, I think it's "don't require individual parts purchases" that needs turned off), that will require buying parts after each node is researched.  It's present in the stock game, at least in 1.8.1, and defaulted "on" in RP-1.

Mind you, this is funds purchasing.  The closest I know of to researching parts individually is Community Tech Tree, which breaks things down a good bit compared to the stock tree.