To further Dave's thought, it's exceptionally valuable if the $100 bonus goes into the IRA and if you can open a Roth. That would be a $100 bonus that is not only tax free now but also when you withdraw its compunded value in decades.
My guess is that the IRS will require all promotional bonuses like this to be taxable, but it is still a nice deal even so. Open a Roth get the bonus and put the bonus in the Roth too. You may not be in a very high tax bracket. So you might pay only a small amount of tax on that $100 bonus.
You mention that you have done little or no investing before. If that means you have no little or no money in a 401k or an IRA, that should be a concern for you -- unless you are very young and are just starting out (in which case it's ok to have done little investing yet). But if a person is in his 30s, he should be expecting that social security will have been cut by the time he gets to be 70, and also that his lifespan will reach to at least 90. That's why socking away as much as you can is a good idea to avoid dying poor, a fate that will befall many people.
