Spads are probably the cheapest plane you can build.

If you expect to fly a lot and take some abuse, an Avenger, Bandit or Predator X are state of the art. All should take .25 to .40 engines, althought the Skoal Bandit is a bit heavy.

I find it funny how people look to the initial cost of a plane as "cheap" and then forget that some of the more expensive kits actually last so long that they are MUCH less expensive to own.

Once you learn about metal geared servos, you're well on your way to this lesson.

If you like to build/repair, I guess it's a non-issue.