There are people who wait long enough and ask if the time is right to invest in Bitcoin. So it’s better to start with a small amount today than to wait for a good hour and never wait. Usually, people who are waiting for the right moment do not dare to investst in Bitcoin. So it's better to start with a small amount today than to wait for a good hour and never wait. Usually, people who are waiting for the right moment do not dare to invest. 30 dollars is not a great amount, but at this time, the owner's motivational impulses become a good psychological factor to continue his investment. In addition, realizing that the amount is not large, the owner has a great opportunity to learn without the risk of large losses, which in the future can lead to the correct distribution of funds.

Do the math OP. 2,5x from here is already a new all time high. How much will we go up in this cycle, by 2025? 3x? 4x? 4x would be 120 000 dollars, so I don't think we're going far beyond that. Some people predict 150, some 200, but even at 150 you're 5x up so your 30 dollars is going to be wort 150. Is 150 a satisfying profit for you? Will this change your life in any way?

You can of course buy bitcoin with $30, just as you can buy it with $10, but that isn't going to make a difference. You'll wait all this time to buy yourself a pair of shoes.

A 30$ start isn't a bad thing already.

I still remember when I started investing into Bitcoin. I started way lesser than your friend (I assume that it's your friend). I invested I think around $20 only to invest into Bitcoin, and I can't forget that time because when I bought it, it was February of 2018, and for those who are into cryptocurrency at that time, or even not you can see what happened on that year.

Now with regards to your friend, 30$ is a good start already I would say (I said it because 30$ is a huge money already).

1. Let him continue to add some more. 30$ today, and then X amount next week or after 2 weeks or next month. Let him do Dollar Cost average since it's the safest approach when it comes to cryptocurrency.
2. Say the truth to him. What I mean is that, tell the truth about how Bitcoin's price moves. Tell him as well that Bitcoin isn't a rich-quick scheme like most people are thinking about it.
3. Guide him. Guide him all the way. Guide him to the point that you can feel that he can invest all by himself already. Guide him since I assume that he is still a beginner. There's no harm in guiding somebody, and it's a good thing since you introduced it to somebody which increases adoption.

We can start with small capital first to train the mentality that the market will definitely give, never start with big money and you are afraid of losing it, in the bitcoin market there are price fluctuations which will certainly give you panic sell or fomo pressure on things going up That kind of thing is bad in my opinion, even if you start with $ 30 if you do it regularly every week or twice a month or once a month for a year the bitcoins you have will certainly be more, speaking of progress depending on whether you do it consistently or not in doing invest in bitcoin, if you hope that with a capital of $ 30 you can make your finances better I think you are just hallucinating, but it will come true if you do it in 2011.

In general I think what you have to say is good advice.
You don't only explain the positive impact, but you also provide an explanation regarding the negative impact.

We cannot foresee what will happen with the market situation. If anyone has invested in Bitcoin at a purchase price much lower than $30K, then they have doubled their profits by now.
Those of us who have just started with a buy price of $29K - $30K still have a chance between losing money and making a profit if the sell price exceeds the current price.

Within 24 hours, Bitcoin experienced a decline in price. For me, the current condition is just a test in the midst of optimism that there will be a higher increase.

It's a very good start, if this is all he can afford from time to time it's a very good beginning, and in a matter of time your bag will grow, remember that a little drop of water can make a mighty ocean, it will take time but it's doable.

He needs to start learning while accumulating Bitcoin all the way, he also needs to have lots of patience, lower your expectations too because with 30$ investment on Bitcoin, it will look like you aren't getting anywhere.

If Bitcoin becomes double right now you will have 60$ worth of Bitcoin, it's going to take time to start seeing impressive gains so work more on adding the 30$ maybe in every two weeks or so.

 amount invested in Bitcoin now that don't worthwhile especially now that the market is yet to reach a new ATH price. Like you said the market-wide and it's also a roller coaster either. The advice you give the person could push him off the edge if the person doesn't know about the use of DCA.
The market doesn't have a minimum amount you can invest, it was the CEX and some DEX that introduce the minimum amount for their own selfish reason.
In the meantime, you need to teach the person how to secure his/her investment.

As long you can afford to lose that amount in the first place then go for it. There is no ideal amount that you can buy and hold Bitcoin even for just 5 bucks.

Just like in my previous posts, we are not financial or investment advisors here. You just disclose to him that Bitcoin does not offer any promises or astronomical guaranteed returns as the market movement is decided by the buyers and sellers.

The price is very unpredictable and it can go up or down at any moment without warning.

In my opinion $30 is not enough to invest in Bitcoin. I would suggest using this amount to try transactions and become familiar with setting up fees and other stuffs related to your bitcoin for testing purposes. However, it is not enough of money that would generate a a decent profit in the future. Bitcoin's current price is already around $30k, which is x1000 times the amount your friend intends to invest. Therefore, investing such a small amount would not result in a substantial return on investment in the long run.

I would like to say that even if Bitcoin's price were to increase a lot, let's say to $60k, your friend would only make a profit of $30, which is not a lot to be honest, so just let him think of it like that... I would suggest advising your friend to buy Bitcoin regularly, maybe every week or every 2-weeks. By doing this, he can potentially make a decent profit over the course of a year or more. It's a good idea to allocate a small percentage of his salary for this purpose.

1.  You won't feel it a lot (as there's no impact in your day to day life)
2.  Over time, the investment can hugely grow and you'll be surprised of how much money you'll make from this investment in couple years (only if he's patient and not touching them)