[baselle]

Saving money, then consistently sticking your savings into a basic low-fee vehicle, like a Vanguard or a Fidelity index fund.

You don't tell us the dollar amounts involved, but at low dollar amounts you should be able to save more money from your paycheck than the increases that you'll get from a growth investment. Even if, say, your investments are returning 12% annually (fantastic results these days), it means that it'll take six years to double your money (rule of 72). Unless we are talking about more than $10,000, you should be able to double your savings more quickly than that.