Relying on others to send products you sell may be a gold mine, but it is most likely a landmine that will explode in your face.
If you are going to take the shipping route, MAKE SURE YOU ARE SELLING WHAT YOU THINK YOU ARE SELLING and make sure your direct shipping partner is as customer oriented as you are. Anything less and you will regret it.
Occasionally, I will send something directly to a customer, but only if I am sure what the customer really wants and only if I am sure that my direct shipping partner is reliable. In general, what I do is get the client's money, have the source of dropshipping sent to me, then IF it meets my expectations, send it back to the client. Sure, that takes more time and costs more money, but there are NO surprises hidden in that way.
If you are going to sell the same thing over and over again from the same direct shipping source, it would be wise to consider buying directly from the distributor, buy it yourself and send it directly to your customer. Most dropshippers will give you a discount if you buy larger quantities instead of one at a time. You can often buy one case at a time. Depending on the item, lots of boxes can be as low as 6 items per box. If you can not afford to buy one case at a time, you simply can not afford to be in business.