Up to date 12.04.

Say what? Is that a version number of something or April 12^th? or December 4^th?

if ($gas_cost < 1) {goto ENDING_BRACE };
stuff here
ENDING_BRACE:
continue here
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Well, I'd reverse that and check for $gas_cost >= 1 and stuff stuff here into that conditional block. No ugly goto needed, no label needed:

if ($gas_cost >= 1) {
    stuff here
}
continue
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Probably stuff here can be tucked away into a subroutine. But...

Have tried variations and read myself into circles.

...it looks like you are coming from C and are trying to grasp the perl goto. Well, read it up.