Analysing what everyone's said here so far, I think the absolute limit for the top solution is:
Rubber launcher for $200
Deflector for $20 or $22
portal catcher for $20 (or maybe $18).
I did manage to get a portal catcher working for $18, but used a $22 deflector, so I was also stuck at $1760.
Theoretically, the limit for a rubber solution would thus be $1762.
But it won't help you now....
I went under, and while my first effort was just 1764, I have now boosted the result to 1790+.
Light solution, of course, since I'm so bad at dark.