Just close your eyes and make the purchase mate. You won't regret it. Moreover, any amount you could afford then, you can still purchase now, though less bit coin but same value which will obviously increase over time. You don't have to buy 1 or more btc before you make a purchase.
I'm just going to wait until the price drops below $1500, even if it means waiting for four years. I'll wait, I'm not in a hurry, BTC will always be here
Then you may end up waiting for long and regretting you did in few months time. Come back here to quote me in that few months time if I ended up wrong.