lostamonkey, if you assume, as your example does, that the tax benefit from the deduction will be the same in every year of your life, then obviously, you should take it earlier rather than later. However, in reality, the benefit can be greater in a subsequent year due to, e.g., higher income. With that in mind, it's very easy to construct examples where the net benefit ends up being higher by delaying the deduction to a later year. I'll leave the construction of those examples as an exercise.
I posted in this thread because the concept of deferring the deduction is especially relevant to people like OP. Presumably they won't be earning $30,000 per year forever. In a couple years they could be earning $150,000 per year instead, and the greater tax benefit at the new income level can more than make up for having deferred receipt of the tax benefit. Despite having low income this year, OP could still intelligently contribute to an RRSP today and then take the deduction once their income has increased.
If OP is barely saving any money, contributing to a TFSA doesn't hurt because they can always take a distribution from the TFSA and contribute the result to an RRSP in the future. However, if OP has enough money to contribute to both, they should definitely take advantage of the RRSP today, despite having low income. For an early retiree who will have low taxable income in retirement, an RRSP without ever taking the deduction is essentially more TFSA space (because the retirement tax rate will be close to 0%), albeit with less generous recontribution rules. The fact that you can take a deduction in a future year just makes it even better.