Is there a place I could just buy the saline injection for breasts? Can I do the injections myself?

Unless done under sterile conditions with a detailed knowledge of the anatomy, this is not something you should consider after watching a YouTube video. You must also understand that this will only last hours.

Don't do that.  You re apt to harm yourself or at least get lumpy uneven breasts and terrible infections.

If you saw the recent TV news story about the newest form of temporary augmentation, injecting normal saline for special occasions, this fluid is sold over the counter as are syringes. BUT please do not try to do this to yourself.  You hav no understanding of the anatomy and how to achieve these injections properly. Implants cannot be injected for enlargement by lay persons.

Even a doctor or surgeon would have second thoughts doing such thing to himself/herself.Be a patient, let doctors do their expertise. 

Saline is easily available at many pharmacies. However, injecting saline in the breast will only give very temporary enlargement. In the US, saline implants are purchased by physicians, surgery centers, or hospitals, and not by individuals.

I am uncertain to the exact content of your question. But, if it refers to adding saline to an already implanted saline device, the answer is no. These implants have a distinct valve that serves as an attachment for sterile tubing that is connected to a bag of sterile, injectable saline solution. The incision needs to be reopened, and this procedure done in a sterile environment. This assumes there is room to ad more saline rather than exchanging the implant for a larger one. Hopefully, your surgeon explained this to you prior to your procedure.

No!! Definitely not!  Saline breast implants are filled through a valve on the surface of the implant (back or front), and this must be done by opening your incision, accessing the valve with sterile, surgical technique, and adding saline. Saline implants also have volume limits, and if you exceed the recommended volume you could damage your implant.  If you try to inject yourself, you could injure yourself and/or your implant, and very likely cause an infection which could lead to losing your implant altogether. There used to be a type of implant that had a remote injection port that you could feel under the skin and add volume postoperatively until the desired volume was reached. This could be done in the office, using sterile technique, and then the valve was removed under local anesthesia. Unless you have this type of device, you will likely need to have your implant exchanged to change your volume (or at least accessed in the operating room so more saline can be added).  Before you do anything, please seek the input and guidance of a Board Certified plastic surgeon. Best of luck to you!

Why do you want to inject saline into your breasts? for temporary enlargement perhaps that lasts a few hours ? Its not something that is done routinely, but certainly should not be done by you at home.