[Career]: Mun exploration is... huh.... expensive.

[Kryxal]

Mun rocket: 19k

The S2 stage made to the moon and became debris.

Given the numbers, you should be able to put your craft on a free-return trajectory and just let the second stage hit Kerbin ... or put it on a Mun-skimming trajectory, run the engine dry by burning retrograde, then jettison and burn retrograde+radial up for a low orbit.

[NovoRei]

Given the numbers, you should be able to put your craft on a free-return trajectory and just let the second stage hit Kerbin ... or put it on a Mun-skimming trajectory, run the engine dry by burning retrograde, then jettison and burn retrograde+radial up for a low orbit.

I could do that. The only problem with that design is stability. You have to use the LF engine during the earlier launch to correct trajectory and to improve TWR at it's own stage.