...it.

This is really a follow-up to my previous question about using Bitcoin to send money to a friend.

I'm new to bitcoin and cryptocurrencies in general.   I recently joined Coinbase.  Today, I wanted to buy $500 worth of bitcoin but was informed that I have a $300 bitcoin purchasing limit.

OK fine.  I just wanted to know, is that a "per day limit"?  Or is that an account balance limit?

In other words, can I buy $300 of bitcoin today, and buy $200 of bitcoin tomorrow, in order to have a balance of about $500 bitcoin in my Coinbase wallet tomorrow?

OR

If I buy $300 of bitcoin today, do I have to remove it from my Coinbase wallet before I can purchase any more bitcoin? 

I asked this question more than once to a Coinbase customer service rep in an online chat, but he did not answer it.  (He may have been a bot; It's so hard these days to tell if service reps are bots or just humans who know nothing about their company's policies.)

I know nothing about bitcoin.

I've been trying to find a way to transfer money to a friend in the Ukraine.  I am in the U.S.

So far, everything I've tried, Western Union, Moneygram, Wise, PayPal, prepaid debit cards, has hit some roadblock.

I'm going to try to figure it out on my own.  But if anyone can give a simple step-by-step description of the procedure, I'd appreciate it.  Thanks.