If it's the last week of the month, odds are that Alison Southwick and Robert Brokamp are going to amble over to the Motley Fool Answers mailbag to find out what it is their listeners really want to know. And for added gravitas and expertise, they've brought in reinforcements: Naima Barnes, a financial planner with Motley Fool Wealth Management, a sister company of The Motley Fool.

In this segment of the podcast, they consider the needs of a 21-year-old listener who wisely has already joined the world of investing via the fee-free trading platform Robinhood. At that age, a person has extremely long-term financial goals -- like saving for retirement -- and nearer-term targets like buying a house, and there is no single "best" tool to get you to all of them.

A full transcript follows the video.

This video was recorded on May 29, 2018.

Alison Southwick: The next question comes from Ravine. "Over the past year, I have slowly begun investing through the app Robinhood using some advice from Stock Advisor. I recently came across IRAs and have a question. As a 21-year-old, is it smarter to max out a Roth IRA and then invest? My primary concern is when pulling money out close to retirement, the tax rates are relatively the same and I'll lose 40% in taxes, whereas with the Roth IRA, I get to keep all the money. I know it's a far way out and a lot could change. Any advice would be greatly appreciated." Well, good for you! A 21-year old? Oh, you are on it.

Brokamp: Very impressive.

Barnes: That's great. I would say that as a 21-year-old, it is great to max out your Roth IRA because you'll be able to enjoy the benefits of that potentially tax-free in retirement. And you can use Stock Advisor to pick the stocks that you're holding inside of your Roth IRA.

Robinhood is great. I use it for just playing around with a few dollars here and there, but it's not where I keep my retirement fund. So, thinking about retirement, I have a Roth IRA that I use for 70 and a half, since that will be when necessarily I'll probably be pulling that money out, but that's not where I keep my retirement fund. So, using Robinhood for just maybe short-term expenses that you might have [meaning like three to five years] and nothing that you'll need today. Or if you're saving up for a house or a trip, that's good for that, but in terms of retirement expenses, I say go Roth IRA and max it out if you can for as long as you can.

Southwick: So, for our listeners who aren't familiar with Robinhood, it's like an online brokerage, but they don't charge you any trading fees. Robinhood is doing very well as a company, right now and it's very attractive. Maybe for our listeners who aren't familiar with it, can you talk a little bit about why someone might use Robinhood?

Barnes: Sure! How Robinhood started was they wanted to be able to allow people to trade stocks without charging any commission fees. Some brokerage companies have fees that are $4, $7. It varies depending on which company you're going with. Robinhood wanted to get away from that, and they started only on mobile phones. They have an app that you can download in the App Store, and you set up your account that way. They have since branched out to providing different types of things you can invest in. You can now invest in ETFs, which might not have been there when they first got on there, as well as bitcoin.

Brokamp: How do you feel about bitcoin, Naima?

Barnes: No, thanks. So, they've gotten to a place where they can offer different types of ways that people can invest and it's pretty cool. You can set it up that it links to your bank. It can do recurring withdrawals to your Robinhood account so that you have a certain amount that's getting put into your account on a regular basis. And the regular Robinhood account is free.

They do have a Robinhood Gold account. I don't know much about that. I think you have to pay for it, but regular Robinhood is free, so it's pretty cool if you want to just look on your phone and do some trading.

Brokamp: And the trick, here, is that Robinhood does not offer IRAs. That's the thing, so it cannot be a retirement account. And I'll just say for Ravine again, awesome for you thinking about saving for retirement at your age. Just know that the amount you can contribute to an IRA of any kind -- you have to have earned income first. If you have a part-time job and you only make $2,000, that's the most you can put in the IRA and you can't max out to the $5,500.

Barnes: You do want to make sure that first you have earned income, second you have enough for emergencie third, max out that IRA with the limit. So, if you work full-time and you make $5,500, go ahead and do it.

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