I happened to have a case that involves 3 currencies:
A - my base currency
B - Paypal always converts everything to this currency, and
C - the currency customer paid with
When I do my journal entries, the way I done it before is ignored C since Paypal auto converts everything to B, but when I start transfer B to A, I can see there is a big chunk of money gone due to forex rates, so I thought to do it properly with my journal entries, I went back to by record how it started when customer paid in C, but when I record the journal from C to B, the base currency is in use, the forex rate became very messy, so I wonder can we disable the Base Currency? So I can set the forex rate properly from C to B, and then B to A.
No you just have 2 currencies: the Base Currency and the Customer Currency. More importantly you actually only have to record the Base Currency because the customer paid using Paypal and you therefore only received the funds in your Base Currency.
Base currency is the default currency. Even if you do not use multi-currency accounting, you might still want to show currency symbol of your home currency on invoices and other documents. This is why base currency form exists.
In your case, there is no need to utilize multi-currency accounting. Multi-currency accounting is for situations when you maintain accounts in other currencies. Even though customer is invoiced in foreign currency, they pay immediately upon invoice being issued so there is no foreign currency accounts receivable balance. And since Paypal auto-converts everything to your home currency, there is not even foreign currency bank account holding any balance.
yes you are right, probably this is the best way and less confusing. I have also setup multicurrency in Paypal, hopefully next time when customer pays it can stay in their own currency, so I can convert to my base currency instead of Paypal auto-convert to currency B