Is it worth buying only one or two of a stock if that’s all you can afford?

I’ll be upfront. I know nothing about investing.

My son wants to get started in investing and seen an article that SpaceEx might go public next year.

He asked me if it does after he turns 18 would it be worth buying only a couple shares if he has the money for it?

I honestly told him I don’t know. He asked about getting a credit card to buy stocks and I flat out told him not to go into credit card debt to buy any stocks, especially when starting out.

Not sure if he would listen to me on that one.

I just don’t know if buying a couple pieces of stock is worthwhile if that’s all you can for for a length of time.