Well. I always buying bitcoin every week for gambling and trading, when i buy the bitcoin i always check the price first and if the time is good i will wait until the price of bitcoin is good.
If you are buying every week, then in any case you are averaging out your cost of purchase.
That is a good strategy.
That's what you should do if you don't have enough money right now, you have to set aside a portion from your earnings and buy bitcoins, consider this buying as profitable because it offers more interest compared to depositing your money with banks.